Specifically designed to attach wood to metal (Max. 4.0mm). Coarse self-tapping thread with wings designed to ream out the timber, this helps the screw achieve Max. R.P.M. without burning out. When the wings hit the metal they will break off to permit the thread to self-tap into the metal. The collated strips are specifically designed to be compatible with all leading power tool brands. The collated strips are specifically designed to be compatible with all leading power tool brands Self-countersinking ribs Coarse 60 self-tapping thread for excellent holding power & rapid insertion Case & core hardened for durability & strength" Thread Dia. mm: 4.8 Length mm: 65 Head Type: Countersunk with Ribs Recess Type: Phillips Point Type: Winged Self-Drilling Finish: Zinc Material: Carbon Steel Effective Thread Length mm: 47 Max Drilling Thickness mm: 4.0 To Suit Timber mm: N/ASize 4.8 x 65 - 500 Pieces Timco Collated Timber to Light Section Screws - Countersunk - Wing-Tip in Silver