A 1/4"-20 to Hot Shoe Adapter* is one of the handiest camera/lighting/audio accessories around. Here at the Nasty Clamps World Domination Headquarters, these adapters are pretty much considered a necessity when doing any sort of photo or video work, as they allow hot shoe mountable equipment (such as a portable strobe, or certain brands of LED lights) to be attached to just about anything with a standard 1/4"-20 tripod screw sticking out of it (like, for example, a Nasty Clamp).
This particular adapter is extremely well made out of cast and machined metal (with a sturdy plastic tension knob), and can stand up to quite a bit of abuse. The clamping jaw is a great feature, and helps to insure that expensive equipment doesn't go sliding off the adapter during the middle of a shot.
Another great feature that's been built into this adapter is that there's a dropped down "divot" or channel which runs through the very middle, and this helps to ensure that the electrical contacts in a strobe's hot shoe foot don't short out on the metal of this adapter.
*From a purely technical point of view, these adapters should be called "1/4-20 to COLD Shoe Adapters." In other words, they have no electrical contacts contained within, and so they are considered "cold." On the other hand -- from a real world point of view -- nobody ever goes out on a photo or video shoot and says: "Quick! Hand me a cold shoe adapter!"