This is a Ball End Set from HPI for use with the HPI Firestorm stadium truck, HPIC0510. Direct replacement parts Black in color,nylon construction Accepts 4mm balls One parts tree containing: Two 12mm ball ends Sixteen 19mm ball ends Installation These are for the Firestorm stadium truck and may be used in other applications that accept a 4mm ball. wm 4/10/07 ir/jxs &