Quality, finish, durability. You really want the 16mm opening which is the tisur shackle. Can use all of my marc jacobs bag straps (with dog leash clips) interchangeably.

These are the best * i have bought, they swivel and are extremely tight and snap like the best of them! They look fantastic with my acrylic keychains. They're great, but the chains are weak so you'll have to be careful or replace frequently.