The store will not work correctly when cookies are disabled.
JavaScript seems to be disabled in your browser.
For the best experience on our site, be sure to turn on Javascript in your browser.
Polyurethane U-Seal, 3.50 Inch OD, 3.13 Inch ID, 0.38 Inch Height
Brand
Hercules Sealing Products
Brand
Hercules Sealing Products
Supplier Part Number
U18-3.12-37B
Alternate Part Numbers
Alternate Part Number
C1DN81
Got a hydraulic cylinder with a 3.50 OD and 3.13 ID bore situation, this u-seal gonna fit that right up?
Question by: Clint W on Aug 13, 2025, 3:06 PM
Those dimensions line up exactly with what this seal is built for. The 3.50 inch OD, 3.13 inch ID, and 0.38 inch height are the hard specs, so if your cylinder matches those numbers, you're good to go. The 0.1875 inch cross section and deep-type profile mean the height runs greater than the cross section, which is worth confirming fits your gland geometry before you press it in.
Answer by: Customer Support on Aug 15, 2025, 8:30 AM
got a cylinder that takes a 3-1/8 ID seal. is this u-seal the right size or am i off a hair
Question by: Dwayne F on Sep 4, 2025, 9:06 PM
Fit comes down to the dimensions on the seal itself. This one is 3.125 inch ID, 3.50 inch OD, with a 0.375 inch height and a 0.1875 inch cross section, so it matches a 3-1/8 inch ID callout.
Answer by: Customer Support on Sep 6, 2025, 5:04 PM
Similar Products
Model Number
Cross Section
I.D.
O.D.
H
Price
Buy Now
U12-0.62-25B
0.125 in
0.625 in
0.875 in
0.25 in
U12-1.00-25B
0.125 in
1 in
1.25 in
0.25 in
U12-1.25-SQB
0.125 in
1.25 in
1.5 in
0.125 in
U18-1.25-SQB
0.1875 in
1.25 in
1.625 in
0.1875 in
U18-1.75-37B
0.1875 in
1.75 in
2.125 in
0.375 in
U18-2.12-SQB
0.1875 in
2.125 in
2.5 in
0.1875 in
U18-2.50-31B
0.1875 in
2.5 in
2.875 in
0.3125 in
U25-1.25-37B
0.25 in
1.25 in
1.75 in
0.375 in
U25-1.50-37B
0.25 in
1.5 in
2 in
0.375 in
U25-2.00-37B
0.25 in
2 in
2.5 in
0.375 in
U25-2.50-37B
0.25 in
2.5 in
3 in
0.375 in
U25-3.00
0.25 in
3 in
3.5 in
0.25 in
U25-3.00-37B
0.25 in
3 in
3.5 in
0.375 in
U25-3.50-37B
0.25 in
3.5 in
4 in
0.375 in
U25-4.00-SQB
0.25 in
4 in
4.5 in
0.25 in
U25-4.50
0.25 in
4.5 in
5 in
0.25 in
U25-5.00
0.25 in
5 in
5.5 in
0.25 in
U12-0.18-25B
0.125 in
0.1875 in
0.438 in
0.25 in
U12-0.25-25B
0.125 in
0.25 in
0.5 in
0.25 in
U12-0.25-SQB
0.125 in
0.25 in
0.5 in
0.125 in
U12-0.31-25B
0.125 in
0.3125 in
0.563 in
0.25 in
U12-0.31-SQB
0.125 in
0.3125 in
0.563 in
0.125 in
U12-0.37
0.125 in
0.375 in
0.625 in
0.125 in
U12-0.50-25B
0.125 in
0.5 in
0.75 in
0.25 in
U12-0.50-SQB
0.125 in
0.5 in
0.75 in
0.125 in
U12-0.56
0.125 in
0.625 in
0.938 in
0.125 in
U12-0.62-SQB
0.125 in
0.625 in
0.875 in
0.125 in
U12-0.68
0.125 in
0.6875 in
0.938 in
0.125 in
U12-0.75-18B
0.125 in
0.75 in
1 in
0.1875 in
U12-0.75-25B
0.125 in
0.75 in
1 in
0.25 in
U12-0.75-SQB
0.125 in
0.75 in
1 in
0.125 in
U12-0.81
0.125 in
0.8125 in
1.063 in
0.125 in
U12-0.87-25B
0.125 in
0.875 in
1.125 in
0.25 in
U12-0.87-SQB
0.125 in
0.875 in
1.125 in
0.125 in
U12-1.00-18B
0.125 in
1 in
1.25 in
0.1875 in
U12-1.00-SQB
0.125 in
1 in
1.25 in
0.125 in
U12-1.06-SQB
0.125 in
1.0625 in
1.313 in
0.125 in
U12-1.12-25B
0.125 in
1.0625 in
1.375 in
0.25 in
U12-1.12-SQB
0.125 in
1.0625 in
1.375 in
0.125 in
U12-1.18
0.125 in
0.188 in
1.438 in
0.125 in
U12-1.18-18B
0.125 in
0.188 in
1.438 in
0.1875 in
U12-1.18-25B
0.125 in
0.188 in
1.438 in
0.25 in
U12-1.25-18B
0.125 in
1.25 in
1.5 in
0.1875 in
U12-1.25-25B
0.125 in
1.25 in
1.5 in
0.25 in
U12-1.37-25B
0.125 in
1.375 in
1.625 in
0.25 in
U12-1.37-SQB
0.125 in
1.375 in
1.625 in
0.125 in
U12-1.50-25B
0.125 in
1.5 in
1.75 in
0.25 in
U12-1.50-SQB
0.125 in
1.5 in
1.75 in
0.125 in
U12-1.62-SQB
0.125 in
1.625 in
1.875 in
0.125 in
U12-1.75-SQB
0.125 in
1.75 in
2 in
0.125 in
U12-2.00
0.125 in
2 in
2.25 in
0.125 in
U12-2.25
0.125 in
2.25 in
2.5 in
0.125 in
U12-2.75
0.125 in
2.75 in
3 in
0.125 in
U15-1.18
0.1563 in
0.188 in
1.5 in
0.1563 in
U15-1.25
0.1563 in
1.25 in
1.563 in
0.1563 in
U15-1.37
0.1563 in
1.375 in
1.688 in
0.1563 in
U18-0.50
0.1875 in
0.5 in
0.875 in
0.1875 in
U18-0.62-31B
0.1875 in
0.625 in
1 in
0.3125 in
U18-0.62-SQB
0.1875 in
0.625 in
1 in
0.1875 in
U18-0.75-31B
0.1875 in
0.75 in
1.125 in
0.3125 in
U18-0.75-SQB
0.1875 in
0.75 in
1.125 in
0.1875 in
U18-0.87-31B
0.1875 in
0.875 in
1.25 in
0.3125 in
U18-0.87-SQB
0.1875 in
0.875 in
1.25 in
0.1875 in
U18-1.00-25B
0.1875 in
1 in
1.375 in
0.25 in
U18-1.00-31B
0.1875 in
1 in
1.375 in
0.3125 in
U18-1.00-37B
0.1875 in
1 in
1.375 in
0.375 in
U18-1.00-SQB
0.1875 in
1 in
1.375 in
0.1875 in
U18-1.12-25B
0.1875 in
1.0625 in
1.5 in
0.25 in
U18-1.12-31B
0.1875 in
1.0625 in
1.5 in
0.3125 in
U18-1.12-SQB
0.1875 in
1.0625 in
1.5 in
0.1875 in
U18-1.18
0.1875 in
0.188 in
1.563 in
0.1875 in
U18-1.25-25B
0.1875 in
1.25 in
1.625 in
0.25 in
U18-1.25-31B
0.1875 in
1.25 in
1.625 in
0.3125 in
U18-1.25-37B
0.1875 in
1.25 in
1.625 in
0.375 in
U18-1.37-25B
0.1875 in
1.375 in
1.75 in
0.25 in
U18-1.37-31B
0.1875 in
1.375 in
1.75 in
0.3125 in
U18-1.37-37B
0.1875 in
1.375 in
1.75 in
0.375 in
U18-1.37-SQB
0.1875 in
1.375 in
1.75 in
0.1875 in
U18-1.50-25B
0.1875 in
1.5 in
1.875 in
0.25 in
U18-1.50-31B
0.1875 in
1.5 in
1.875 in
0.3125 in
U18-1.50-37B
0.1875 in
1.5 in
1.875 in
0.375 in
U18-1.50-SQB
0.1875 in
1.5 in
1.875 in
0.1875 in
U18-1.62
0.1875 in
1.625 in
2 in
0.1875 in
U18-1.62-25B
0.1875 in
1.625 in
2 in
0.25 in
U18-1.62-31B
0.1875 in
1.625 in
2 in
0.3125 in
U18-1.62-37B
0.1875 in
1.625 in
2 in
0.375 in
U18-1.62-SQB
0.1875 in
1.625 in
2 in
0.1875 in
U18-1.75-25B
0.1875 in
1.75 in
2.125 in
0.25 in
U18-1.75-31B
0.1875 in
1.75 in
2.125 in
0.3125 in
U18-1.75-SQB
0.1875 in
1.75 in
2.125 in
0.1875 in
U18-1.87-37B
0.1875 in
1.875 in
2.25 in
0.375 in
U18-1.87-SQB
0.1875 in
1.875 in
2.25 in
0.1875 in
U18-2.00-31B
0.1875 in
2 in
2.375 in
0.3125 in
U18-2.00-37B
0.1875 in
2 in
2.375 in
0.375 in
U18-2.00-SQB
0.1875 in
2 in
2.375 in
0.1875 in
U18-2.12-25B
0.1875 in
2.125 in
2.5 in
0.25 in
U18-2.25-37B
0.1875 in
2.25 in
2.625 in
0.375 in
U18-2.25-SQB
0.1875 in
2.25 in
2.625 in
0.1875 in
U18-2.37-SQB
0.1875 in
2.375 in
2.75 in
0.1875 in
U18-2.50-25B
0.1875 in
2.5 in
2.875 in
0.25 in
U18-2.50-37B
0.1875 in
2.5 in
2.875 in
0.375 in
U18-2.50-SQB
0.1875 in
2.5 in
2.875 in
0.1875 in
U18-2.62-37B
0.1875 in
2.625 in
3 in
0.375 in
U18-2.62-SQB
0.1875 in
2.625 in
3 in
0.1875 in
U18-2.75-37B
0.1875 in
2.75 in
3.125 in
0.375 in
U18-2.75-SQB
0.1875 in
2.75 in
3.125 in
0.1875 in
U18-2.87
0.1875 in
2.875 in
3.25 in
0.1875 in
U18-3.00
0.1875 in
3 in
3.375 in
0.1875 in
U18-3.00-37B
0.1875 in
3 in
3.375 in
0.375 in
U18-3.12-37B
0.1875 in
3.125 in
3.5 in
0.375 in
U18-3.12-SQB
0.1875 in
3.125 in
3.5 in
0.1875 in
U18-3.50-37B
0.1875 in
3.5 in
3.875 in
0.375 in
U18-3.62-37B
0.1875 in
3.625 in
4 in
0.375 in
U18-3.62-SQB
0.1875 in
3.625 in
4 in
0.1875 in
U18-4.00-37B
0.1875 in
4 in
4.375 in
0.375 in
U25-0.75
0.25 in
0.75 in
1.25 in
0.25 in
U25-0.93
0.25 in
0.8125 in
1.438 in
0.25 in
U25-1.00-37B
0.25 in
1 in
1.5 in
0.375 in
U25-1.00-SQB
0.25 in
1 in
1.5 in
0.25 in
U25-1.12
0.25 in
1.0625 in
1.625 in
0.25 in
U25-1.12-37B
0.25 in
1.0625 in
1.625 in
0.375 in
U25-1.18
0.25 in
0.188 in
1.688 in
0.25 in
U25-1.25-SQB
0.25 in
1.25 in
1.75 in
0.25 in
U25-1.37
0.25 in
1.375 in
1.875 in
0.25 in
U25-1.37-37B
0.25 in
1.375 in
1.875 in
0.375 in
U25-1.50-31B
0.25 in
1.5 in
2 in
0.3125 in
U25-1.50-SQB
0.25 in
1.5 in
2 in
0.25 in
U25-1.75
0.25 in
1.75 in
2.25 in
0.25 in
U25-1.75-37B
0.25 in
1.75 in
2.25 in
0.375 in
U25-1.87-37B
0.25 in
1.875 in
2.375 in
0.375 in
U25-2.00-31B
0.25 in
2 in
2.5 in
0.3125 in
U25-2.00-SQB
0.25 in
2 in
2.5 in
0.25 in
U25-2.12-37B
0.25 in
2.125 in
2.625 in
0.375 in
U25-2.25
0.25 in
2.25 in
2.75 in
0.25 in
U25-2.25-37B
0.25 in
2.25 in
2.75 in
0.375 in
U25-2.37-37B
0.25 in
2.375 in
2.875 in
0.375 in
U25-2.50-SQB
0.25 in
2.5 in
3 in
0.25 in
U25-2.62-37B
0.25 in
2.625 in
3.125 in
0.375 in
U25-2.75-37B
0.25 in
2.75 in
3.25 in
0.375 in
U25-2.75-SQB
0.25 in
2.75 in
3.25 in
0.25 in
U25-3.25-37B
0.25 in
3.25 in
3.75 in
0.375 in
U25-3.50
0.25 in
3.5 in
4 in
0.25 in
U25-3.50-SQB
0.25 in
3.5 in
4 in
0.25 in
U25-3.75-37B
0.25 in
3.75 in
4.25 in
0.375 in
U25-3.75-SQB
0.25 in
3.75 in
4.25 in
0.25 in
U25-4.00-37B
0.25 in
4 in
4.5 in
0.375 in
U25-4.00-50D
0.25 in
4 in
4.5 in
0.5 in
U25-4.00-56B
0.25 in
4 in
4.5 in
0.5625 in
U25-4.50-37B
0.25 in
4.5 in
5 in
0.375 in
U25-4.50-56B
0.25 in
4.5 in
5 in
0.5625 in
U25-4.50-62B
0.25 in
4.5 in
5 in
0.625 in
U25-5.00-37B
0.25 in
5 in
5.5 in
0.375 in
U25-5.50
0.25 in
5.5 in
6 in
0.25 in
U25-5.50-37B
0.25 in
5.5 in
6 in
0.375 in
U25-5.50-56B
0.25 in
5.5 in
6 in
0.5625 in
U31-1.00-50B
0.3125 in
1 in
1.625 in
0.5 in
U31-1.25
0.3125 in
1.25 in
1.875 in
0.3125 in
U31-1.25-37B
0.3125 in
1.25 in
1.875 in
0.375 in
U31-1.37-37B
0.3125 in
1.375 in
2 in
0.375 in
U31-1.37-SQB
0.3125 in
1.375 in
2 in
0.3125 in
U31-1.50
0.3125 in
1.5 in
2.125 in
0.3125 in
U31-1.75-37B
0.3125 in
1.75 in
2.375 in
0.375 in
U31-1.87
0.3125 in
1.875 in
2.5 in
0.3125 in
U31-2.00
0.3125 in
2 in
2.625 in
0.3125 in
U31-2.00-50B
0.3125 in
2 in
2.625 in
0.5 in
U31-2.25-50B
0.3125 in
2.25 in
2.875 in
0.5 in
U31-2.37
0.3125 in
2.375 in
3 in
0.3125 in
U31-2.50
0.3125 in
2.5 in
3.125 in
0.3125 in
U31-2.50-50B
0.3125 in
2.5 in
3.125 in
0.5 in
U31-2.75
0.3125 in
2.75 in
3.375 in
0.3125 in
U31-2.75-50B
0.3125 in
2.75 in
3.375 in
0.5 in
U31-2.87
0.3125 in
2.875 in
3.5 in
0.3125 in
U31-3.00-50B
0.3125 in
3 in
3.625 in
0.5 in
U31-3.37-50B
0.3125 in
3.375 in
4 in
0.5 in
U31-4.00
0.3125 in
4 in
4.625 in
0.3125 in
U31-4.00-56B
0.3125 in
4 in
4.625 in
0.5625 in
U31-4.37
0.3125 in
4.375 in
5 in
0.3125 in
U31-4.50
0.3125 in
4.5 in
5.125 in
0.3125 in
U37-1.25
0.375 in
1.25 in
2 in
0.375 in
U37-1.75
0.375 in
1.75 in
2.5 in
0.375 in
U37-2.50-50B
0.375 in
2.5 in
3.25 in
0.5 in
U37-2.75
0.375 in
2.75 in
3.5 in
0.375 in
U37-3.25-50B
0.375 in
3.25 in
4 in
0.5 in
U37-3.50
0.375 in
3.5 in
4.25 in
0.375 in
U37-3.75-50D
0.375 in
3.75 in
4.5 in
0.5 in
U37-4.00-62B
0.375 in
4 in
4.75 in
0.625 in
U37-4.25-50D
0.375 in
4.25 in
5 in
0.5 in
U37-4.25-62B
0.375 in
4.25 in
5 in
0.625 in
U37-4.25-SQB
0.375 in
4.25 in
5 in
0.375 in
U37-4.50-62B
0.375 in
4.5 in
5.25 in
0.625 in
U37-5.00-62B
0.375 in
5 in
5.75 in
0.625 in
U37-5.25
0.375 in
5.25 in
6 in
0.375 in
U37-5.25-50D
0.375 in
5.25 in
6 in
0.5 in
U37-6.25-50D
0.375 in
6.25 in
7 in
0.5 in
U50-2.00-SQB
0.5 in
2 in
3 in
0.5 in
U50-2.50
0.5 in
2.5 in
3.5 in
0.5 in
