This is an optional Aluminum Cooling Head from GH Racing for the Traxxas 3.3 Engine.FEATURES: Aluminum construction, silver in color Removable head button 8 scallops cut into side of cylinder headINCLUDES: One complete cylinder headREQUIRES: Installation on engine using stock head screws and gasketSPECS: Length: 2" (51mm) Diameter: 1-1/2" (39mm)Golden HorizonsPart GHH02567