M4 x 38mm. Drill Size. 8mm Fixing Thickness 17mm Trade Pack of 20. High performance cavity fixings, ideal for fixing heavy objects securely on soft faced partition boards, plasterboard, hardboard plywood. The screw and fixture can be removed and re-used. (e.g. When moving radiators for re-decoration) using a standard slotted or pozidriv screwdriver. A special setting tool (RAWAT88) is available for fast repetitive fixing. Typical uses: Coat hooks to hollow doors, shelves and bathroom accessories to standard plasterboard, radiators and kitchen cabinets to double thickness and tiled plasterboard.