Square O-Ring (ID:15 mm, CS:2 mm, OD:19 mm), 4PK The o ring is placed into a groove to secure them in place, and then compressed between two surfaces..
R-233 Square O-Ring (ID: 2 7/8", CS 1/8", OD 3 1/8"), 20PK The o ring is placed into a groove to secure them in place, and then compressed between two surfaces..