"I bought some of these with the intention of using them to hang my guitars on the walls of a sliding doored cupboard to keep them out of the way, but unfortunately the gap between the prongs is too narrow and the metal is too solid to bend them outwards. I have instead used them as intended. 4 screwed horizontally into angled joists in my loft to hold my fishing rods, and the rest into a batten of wood in my garage to hang the rake, spade, brush, etc.
All you need to do is drill a suitably sized pilot hole and manually wind the hooks in. They are coated (apart from the screw of course) in rubbery plastic which will prevent them from rusting.
These are priced at £1 more in other DIY warehouses. Unlike another DIY chain Screwfix doesn't sell the same hooks with a wider spacing between the prongs, which would be the right size for the guitar necks to fit between, but I reconsidered because the other DIY chains charge too much and more importantly my guitars are very heavy and too expensive to place total trust on one screw into a wall plug or wooden batten. The hooks are really strong, but they will only bear as much weight as the wall plugs and / or surface they are screwed into will bear."