These are Ball Bearings from Tamiya.

FEATURES:

Usable with Tamiya's TT-01 chassis cars (Expert Built).
Ball bearings are the most essential part for tuning up your R/C
car. Enables heightened top speed and longer component life.
Sealed, stainless steel ball bearing set.
#1150 bearings are used with spur gears.
#1280 bearings are used with differential gears.

INCLUDES:

(12) #1150 5 x 11mm Ball Bearings
(4) #1280 8 x 12mm Ball Bearings

REQUIRES: To replace bearings refer to TT-01 chassis instruction manual