Quick-release rubber strap - You can change the strap in seconds without using any watch tools. This FKM fluoroelastomer rubber watch band collection has a quick-release spring bar mechanism, which can be installed and removed quickly and easily just with your fingertip. FKM rubber is made to stand harsh conditions; it's waterproof, so it is excellent for outdoor use, and that's why FKM rubber straps are so popular among divers and adventurers. Available watch lug options : 20mm, 22mm and 24mm