Screw factory Product Description Stainless steel Hex Head Wood Screws have good chemical resistance and are ideal for ACQ treated (arsenic-free) wood. Also called square head bolts, they have a hexagon head that can be held firmly with a wrench. They press the thread into the material to ensure a firm fixation. To prevent splitting, drill a pilot hole slightly smaller than the screw. They may be slightly magnetic. The length is measured from under the head. Product Details Drive StyleExternal Hex Approximate Threads per Inch9 Thread DirectionRight Hand ThreadingPartially threaded Tip TypePointed System of MeasurementInch Material18-8 Stainless steel For use inWood Specifications MetASME B18.2.1 Product equipment Test equipment Our factory Certificate Warehouse-MapScrew factory website:http://www.jgscrewnut.com/screw-bolt/screw/