100 GI JOE 3-3/4" O-RING REPLACEMENT WAISTBAND O-RINGS From Professor Foam&trade; Up for sale is 100 pieces of the o-ring needed to replace the waistband on a 3-3/4" G.I. Joe action figure. INSIDE DIAMETER: 7/16" OUTSIDE DIAMETER: 5/8" CROSS SECTION: 3/32" Genuine Professor Foam products!