TRVBBZ Revo Boom Racing High Performance Full Ball Bearings Set Rubber Sealed (40 Total) Revo (4) 12 x 18 x 4 (3) 10 x 15 x 4 (3) 5 x 8 x 2.5 (13) 5 x 11 x 4 (11) 6 x 12 x 4 (2) 8 x 16 x 5 (4) 6 x 13 x 5