The Halo ceramic series of bearings are a high quality steel/chrome bearing with metal shields and ceramic Si3N4 balls. They also contain our highly developed high speed/temp oil instead of grease for maximum performance. These bearings have been tested and proven by many racers.
10x15x4 Halo bearing by Avid Racing Concepts is the standard bearing for the Adam Drake 2 Losi truck in the rear hubs, Xray hubs and 1/8th scale on-road hubs. Check your manual for the correct size for you vehicle if you are not certain.