R-228 Square O-Ring (ID: 2 1/4", CS 1/8", OD 2 1/2"), 16PK The o ring is placed into a groove to secure them in place, and then compressed between two surfaces..
.R-116 Square O-Ring (ID: 3/4", CS 3/32", OD 15/16"), 12PK The o ring is placed into a groove to secure them in place, and then compressed between two surfaces.