McMaster-Carr logo
    Enter e-mail addresses in the fields below
    Message
    Cancel
    Comments
    E-mail address (if you would like a response)
    122 Products

    O-Ring-Loaded U-Cup Seals

    Image of Product. Side 1. Front orientation. U-Cup Seals. O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.
    Image of Product. Side 2. Back orientation. U-Cup Seals. O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.
    Image of Product. Profile. Front orientation. CrossSection view. U-Cup Seals. O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.

    Side 1

    Side 2

    Profile

    Image of Attribute. Rod Installation. Front orientation. Contains Annotated. O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.
    Image of Attribute. Piston Installation. Front orientation. Contains Annotated. O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.

    Rod Installation

    Piston Installation

    Also known as loaded-lip seals and PolyPaks, an O-ring secures these U-cups to the rod or piston for better sealing performance at lower pressures than unsupported U-cup seals. Because U-cups have a sealing lip on both the inside and outside edges, they can be used for rod and piston sealing. Pistons require two seals—install one facing in each direction.
    Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.
    For Rod
    Sealing
    For Piston
    Sealing
    O-Ring
    For Rod
    Dia.
    For Groove
    Dia.
    For Bore
    Dia.
    For Groove
    Dia.
    Max. Speed,
    ft/sec
    Max. Pressure,
    psi
    Temp. Range,
    ° F
    Hardness
    Color
    Hardness
    Color
    Each
    Polyurethane Rubber with Buna-N O-Ring
     
    For 0.138" Wide Grooves
    1/8"0.375"3/8"0.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    3/16"0.438"7/16"0.187"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1/4"0.500"1/2"0.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    5/16"0.563"9/16"0.312"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    3/8"0.625"5/8"0.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    7/16"0.688"11/16"0.437"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1/2"0.750"3/4"0.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    5/8"0.875"7/8"0.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    3/4"1.000"1"0.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    7/8"1.125"1 1/16"0.875"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1"1.250"1 1/4"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/8"1.375"1 3/8"1.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/4"1.500"1 1/2"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
     
    For 0.172" Wide Grooves
    3/4"1.063"1 1/16"0.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1"1.313"1 5/16"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 3/16"1.500"1 1/2"1.187"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 3/8"1.688"1 11/16"1.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
     
    For 0.206" Wide Grooves
    3/16"0.563"9/16"0.187"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    3/8"0.750"3/4"0.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    7/16"0.813"13/16"0.437"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1/2"0.875"7/8"0.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    5/8"1.000"1"0.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    3/4"1.125"1 1/8"0.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    7/8"1.250"1 1/4"0.875"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1"1.375"1 3/8"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/8"1.500"1 1/2"1.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 3/16"1.563"1 9/16"1.187"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/4"1.625"1 5/8"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 3/8"1.750"1 3/4"1.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/2"1.875"1 7/8"1.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 5/8"2.000"2"1.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 7/8"2.250"2 1/4"1.875"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2"2.375"2 3/8"2.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2 1/8"2.500"2 1/2"2.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2 3/8"2.750"2 3/4"2.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2 1/2"2.875"2 7/8"2.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2 5/8"3.000"3"2.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2 3/4"3.125"3 1/8"2.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
     
    For 0.275" Wide Grooves
    1/2"1.000"1"0.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    5/8"1.125"1 1/8"0.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    3/4"1.250"1 1/4"0.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    7/8"1.375"1 3/8"0.875"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1"1.500"1 1/2"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/8"1.625"1 5/8"1.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 3/16"1.688"1 11/16"1.187"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/4"1.750"1 3/4"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 3/8"1.875"1 7/8"1.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 1/2"2.000"2"1.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    1 3/4"2.250"2 1/4"1.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2"2.500"2 1/2"2.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2 1/4"2.750"2 3/4"2.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black00000000000
    2 1/2"3.000"3"2.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 3/4"3.250"3 1/4"2.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3"3.500"3 1/2"3.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3 1/2"4.000"4"3.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3 3/4"4.250"4 1/4"3.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    4"4.500"4 1/2"4.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    4 1/2"5.000"5"4.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    4 3/4"5.250"5 1/4"4.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    6 1/2"7.000"7"5.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
     
    For 0.343" Wide Grooves
    1 3/8"2.000"2"1.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 7/8"2.500"2 1/2"1.875"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2"2.625"2 5/8"2.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 3/8"3.000"3"2.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    5 3/8"6.000"6"5.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    7 3/8"8.000"8"7.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
     
    For 0.413" Wide Grooves
    1 1/4"2.000"2"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    1 1/2"2.250"2 1/4"1.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    1 5/8"2.375"2 3/8"1.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    1 3/4"2.500"2 1/2"1.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2"2.750"2 3/4"2.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 1/8"2.875"2 7/8"2.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 1/4"3.000"3"2.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 1/2"3.250"3 1/4"2.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 3/4"3.500"3 1/2"2.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3"3.750"3 3/4"3.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3 1/4"4.000"4"3.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3 1/2"4.250"4 1/4"3.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3 3/4"4.500"4 1/2"3.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    4 3/4"5.500"5 1/2"4.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
     

    High-Stability O-Ring-Loaded U-Cup Seals

    Image of Product. Side 1. Front orientation. U-Cup Seals. High-Stability O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.
    Image of Product. Side 2. Back orientation. U-Cup Seals. High-Stability O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.
    Image of Product. Profile. Front orientation. CrossSection view. U-Cup Seals. High-Stability O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.

    Side 1

    Side 2

    Profile

    Image of Attribute. Rod Installation. Front orientation. Contains Annotated. High-Stability O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.
    Image of Attribute. Piston Installation. Front orientation. Contains Annotated. High-Stability O-Ring-Loaded U-Cup Seals, Polyurethane Rubber.

    Rod Installation

    Piston Installation

    Also known as Type B seals, loaded-lip seals, and PolyPaks, these U-cups are wider than our other O-ring-loaded U-cup seals for better stability. An O-ring secures them to the rod or piston, preventing leaks at low pressure and as the seal wears. Because U-cups have a sealing lip on both the inside and outside edges, they can be used for rod and piston sealing. Pistons require two seals—install one facing in each direction.
    Note: Maximum performance values cannot be achieved simultaneously; for example, speed is affected by pressure, temperature, and other operating conditions.
    For Rod
    Sealing
    For Piston
    Sealing
    O-Ring
    For Rod
    Dia.
    For Groove
    Dia.
    For Bore
    Dia.
    For Groove
    Dia.
    Max. Speed,
    ft/sec
    Max. Pressure,
    psi
    Temp. Range,
    ° F
    Hardness
    Color
    Hardness
    Color
    Each
    Polyurethane Rubber with Buna-N O-Ring
     
    For 0.206" Wide Grooves
    5/8"0.875"7/8"0.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3/4"1.000"1"0.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1"1.250"1 1/4"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/4"1.500"1 1/2"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
     
    For 0.253" Wide Grooves
    1 3/4"2.125"2 1/8"1.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
     
    For 0.275" Wide Grooves
    1/4"0.500"1/2"0.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    3/8"0.625"5/8"0.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1/2"0.750"3/4"0.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    5/8"0.875"7/8"0.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    3/4"1.000"1"0.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    7/8"1.125"1 1/8"0.875"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1"1.250"1 1/4"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/16"1.313"1 5/16"1.062"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/8"1.375"1 3/8"1.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/4"1.500"1 1/2"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/4"1.625"1 5/8"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 3/8"1.625"1 5/8"1.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/2"1.750"1 3/4"1.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    2"2.250"2 1/4"2.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    2 1/8"2.375"2 3/8"2.125"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
     
    For 0.343" Wide Grooves
    7/8"1.250"1 1/4"0.875"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1"1.375"1 3/8"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 3/8"1.750"1 3/4"1.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/2"1.875"1 7/8"1.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 5/8"2.000"2"1.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 3/4"2.125"2 1/8"1.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    2"2.375"2 3/8"2.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
     
    For 0.413" Wide Grooves
    1"1.500"1 1/2"1.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/4"1.750"1 3/4"1.250"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 3/8"1.750"1 3/4"1.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/2"1.875"1 7/8"1.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 1/2"2.000"2"1.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 5/8"2.000"2"1.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    1 3/4"2.250"2 1/4"1.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    2"2.500"2 1/2"2.000"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black000000000000
    2 3/8"2.875"2 7/8"2.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 1/2"2.875"2 7/8"2.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 1/2"3.000"3"2.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    2 3/4"3.250"3 1/4"2.750"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3 1/2"4.000"4"3.500"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
    3 5/8"4.125"4 1/8"3.625"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
     
    For 0.550" Wide Grooves
    3 3/8"4.000"4"3.375"1.65,000-65 to 300Durometer 90A (Hard)BlackDurometer 70A (Medium)Black0000000000000
     
    back to top