Hex head self drilling screw with flange provides large bearing surface, which protect the connecting surface during assembly. Our company offers hex flange head drilling screw with EPDM washer(roofing screw), in which the EPDM washer offers sealing functions,to resistant water leaks during its working.Hex washer head self drilling screw is for metal to metal applications, mostly for roofing to metal frames fastening. Various color painting for outdoor decoration applications,