I bought 2 of these several years ago when I was installing my home theater speakers, and paid $59 for each. I found out quickly that I couldn't place one of the mounts where I wanted one of the speakers, so I never used it. The one I did use has been holding a 15 Lb surround speaker with no problem at all. The third picture shows the speaker that I mounted (after I painted it black).

The Theater series speaker mounts provide all the strength and stability you need to mount a theater size speaker. The THRS model is for back of speaker mounting. May be used in an inverted application. The Theater series speaker mounts offer a full side to side positioning and over 180° of tilt adjustment.