5.5 x 85 - Metal Construction Timber to Heavy Section Screws - Countersunk - Wing-Tip - Self-Drilling - Exterior - Silver Organic - Box of 100
Specifically designed to attach wood to metal (Max. 12mm). Metric thread with wings designed to ream out the timber, so the screw can 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.