The Halo series of bearings are a high quality steel/chrome bearing with rubber seals. These bearings have been tested and proven by many racers. Bearings in stock right now are black seals.
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.