These stainless steel scissor snaps can swivel and are used with dog leashes, reins, keys and harnesses. Swivel scissors snaps are also commonly referred to as trigger snaps and lobster claw snap hooks. The advantage of scissor snaps over other types of similar size leash snaps is that they can open much further to simplify a connection to a ring or loop. The 1 inch size refers to the inside dimensions to accommodate a leather strap or nylon strap.
This is a very high quality scissor snap. Was particularly interested in stainless steel for outdoor/sweaty application. You have to pay for quality but this snap is worth it.