Review on Lenink Plastic Drywall Anchors for Efficient Drilling and Secure Mounting by Michael Boyce

Great! They are very durable - they can easily be hammered (after drilling the pilot holes). After inserting the screw, they appear to be very firmly attached to the wall. My $2,000 guitar (10+ pound, electric bass) hangs with four of them in its mount (the larger ones are rated at 200 pounds) and every time I hang the guitar up (often multiple times a day) there's absolutely no sign they're getting weaker. In comparison, the regular plastic anchors I have on a few other guitars creak a bit when I hang them up. This is one of those amazing finds.