Detailed Product Description special screw,wood screw,this product is hex head and slot recess .we also can produce other recess accoring to customer's requestdin571 size:from m4 to m30length:from 1 to 24 inchesinch size lag screw:size:from 1/4 to 1inchessurface:zp,yzp,zinc black,nickel ,brass plated,HDG,dacrometmaterial:carbon steel,stainless steel,brass