SECURITY HEADED RACK SCREWS These Security Headed Rack Screws are designed to deter the thief from removing equipment from racks. Made from stainless steel to prevent a thief shearing the head off conventionally with a hammer and sharp chisel. The head is domed so that it cannot be gripped with pliers. The head has an Allen key hole but with a protruding centre pin that makes the insertion of a conventional key impossible. Size M6 x 16mm long. As used in Public Telephone Booths etc. Not suitable for SKB products due to thread size.