I love these things. Especially if you're into bondage, they're some of the most oddly-useful accessories to have. They can clip cuffs together, clip a cuff to any D-ring or O-ring, clip cute hanging charms onto BDSM collars, clip cuffs to furniture, and more.
If I'm using any of my restraints, these aren't far behind. I keep a set of four with me at all times whenever I travel with my kink stuff too! (They're THAT useful!)