Very handy if you use multiple boxes.

I use a wrist strap with a Metro BlackRapid XPRO 1 Fuji and Fuji EX-1. I bought a FastenR3 for each device. When I change case, I unclipped the strap first then I clipped in the second - a matter of seconds.

This clip is of excellent quality and finish is exemplary. It also feels upon purchase (therefore price). Coupled with BlackRapid strap, you will not have to worry about escaping your device: the whole is frankly solid.

Good photo ^^