The outside diameter of the ring has a crush lip providing extra interference in the groove. A bead on the shoulder stops contaminates from entering through the groove. The inside diameter is ribbed to prevent pressure traps between the wiper and rod seal.
ST-XL (Hallite 520) wipers are direct replacements for ST or D wipers.
1 X 1.274 X .107 AN Wiper URE
2 X 2.304 X .107 AN Wiper URE
1 1/4 X 1.524 X .107 AN Wiper URE
1 1/2 X 1.804 X .107 AN Wiper URE