Set of 2 Stainless Steel Base Screws / Ice Screws For securing cargo on floating docks, rafts, etc., and for fixing parasol stands. For wind対策 (countermeasures). Screw size: M6 Underhead length: Approximately 30mm+ Designed to prevent washers from falling off. Unlike base screws sold at fishing tackle stores, these are made of stainless steel, making them rust-resistant and strong. Significantly cheaper than purchasing ice screws on A●mazon.