Material/Facts: Stainless steel in A4 (acid-proof) quality, Torx20 Function: Intended for mounting pressure-treated timber, e.g., in saltwater, pools, and hot tubs. The screw head should always be countersunk at least 2-3mm into the material to avoid protruding when the pressure-treated timber dries. This screw is also suitable for use with Larch decking, as the acid in larch is aggressive, thus the larch decking must be pre-drilled. Recommended rotational speed: 2000-4000 rpm. Screw consumption: approx. 30 pcs/m²