These screw on jibs are really only useful as foot jibs- even on a vertical wall. I used about 10 of them as hand holds and the rest as feet because they are so small. I have them on a vertical garage wall and even there they are super hard to use. I use a few of them for routes I use for training, but only sparingly because they will cause injury if you're not careful. Also, don't use a screw gun
This review was written in the old system and had content requirements that are different than reviews written today.