Lined with a 5mil. Soft fabric lined neoprene, but this one goes further with a durable locking system! Just try and get out of these! Also features eyelet lined holes for added security. The set comes with 2 – 2 1/2 wide buckle- adjust cuffs, 1 – 3 1/2 double snap lock, 2 – 2 3/8 stainless steel spring snaps for attaching elsewhere. Locks & keys included. Fit’s a 4 – 9 wrist. Features highly polished stainless steel buckles and Dee rings, they will never rust or tarnish.