General description These TIMCO Self-Drilling Wing-Tip Steel to Timber Light Section Exterior Silver Screws are specifically designed for attaching wood to metal, with a maximum thickness of 5mm. The screws feature a coarse self-tapping thread with wings that ream out the timber, allowing for optimal performance without burning out. Technical specifications Dimensions: 5.5 x 50 mm Maximum metal thickness: 5 mm Usage Ideal for attaching wood to metal structures. Wings break off upon contact with metal to allow the thread to engage properly.