The thickness of the straight shank part of this molybdenum screw is not sufficient for drywall. It's made for something that's only 1/4-3/8" thick, not the typical 1/2-5/8" thick drywall. I tried one in a spare piece of drywall and it just twisted instead of opening. The short stem prevented the "legs" from opening causing it to simply rotate in the foil and put too much pressure on the spikes. All anchors in this set were the same thickness.