Hardened stainless steel Torx TX25 drive 5.5mm x 40mm long. Small cylinder head screws for hardwood decking, boardwalks, pontoons or jetties. The top thread helps hold the top board in place.

A minimum screw-in depth of 4 x the diameter must be ensured. A screw-in depth of 8 x the diameter should be achieved depending on the wood. Not suitable for salt water environments A4 is preferred.