Hollow wall anchor (cavity wall anchor) is specially designed for hollow substrates like plasterboard, cavity panel and plywood. It consists of cross countersunk screw, cone nut and slotted metal sleeve. When tightening the screw, the sleeve collapses and expands behind the panel to create firm support. For medium loads mounting shelves, mirrors and light fittings. Pre-drilling required. Sizes M3~M6. Zinc plated available.