R-355 Square O-Ring (ID: 5 1/4", CS 3/16", OD 5 5/8"), 4PK The o ring is placed into a groove to secure them in place, and then compressed between two surfaces..
R-335 Square O-Ring (ID: 2 3/4", CS 3/16", OD 3 1/8"), 48PK The o ring is placed into a groove to secure them in place, and then compressed between two surfaces..
.R-012 Square O-Ring (ID: 3/8", CS 1/16", OD 1/2"), 240PK The o ring is placed into a groove to secure them in place, and then compressed between two surfaces.