Set of six 3mm x 15mm cap-head machine screws (hex drive). Used to secure cooling head to engine block on TRX 2.5 engine. Use Traxxas stock and hop-up replacement parts to get the most out of your Traxxas RTR vehicles. This product is made from high quality materials and designed for long-lasting performance. This is replacement hardware for use on Traxxas vehicles; consult your user's manual for exact parts listings.