... tapping screws Carbon steel or stainless steel,Hardened quality Counter sunk head tapping screws Carbon steel or stainless steel, zinc ... ,ST4.2,ST4.8,ST5.5,ST6.3Length:6mm-100mm full thread or part threadFinish treatment: Zinc-plated, yellow zinc-plated ... plated, brass plated, black phosphated or plain if sus material Counter Sunk Head Philips Self Tapping Screws