I find this is the best option when you can't reach a stud on the wall. Guys you just stuck in the wall keep getting pulled out of me, either all at once or little by little over time. I first found them at Home Depot a few years ago, but now I buy them from Revain because it's cheaper than locally. You just need to make sure you know what thickness of drywall/wallboard you have beforehand or they may not pop out and snap into place. Once in place, the only way to remove them is to drill them out, which is fairly easy as they are plastic. After all, once properly installed, they are reliable and you don't have to worry about them pulling out over time. I've used them to assemble glass shelves, wooden shelves etc and they all stand to this day.