18701750-375B URING 1-3/4X 2-1/8 X 3/8 X 3/16 TYPE B ROD

This Seal is mostly used a Rod seal but sometimes it is used as a Piston Seal too. The reason this is called a U-Seal is because the inside profile is U-Shaped, sealing both on top and bottom.
I also use this seal in the kits I build as a replacement for OEM Part Number 834499M1

18701750-375B
U RING 1-3/4X2-1/8X3/8X3/16 TYPE B ROD Replaces O.E.M. Part Number O.E.M 834499M1