Traxxas 3937 Hex-Drive Button-Head Machine Screws, 4x12mm (set of 6) Set of six 4mm x 12mm screws button-head machine style Hex drive heads Use Traxxas stock and hop-up replacement parts to get the most out of you Traxxas RTR vehicles! This product is made from high quality materials, and designed for lasting performance. This is replacement hardware for use on Traxxas vehicles, consult your user's manual for exact parts listings.