4x10x4 Halo bearing by Avid Racing Concepts is most commonly used in the brushless motors, fishing reels and helicopters. Check your manual for the correct size for your vehicle if you are not certain.
Motors Used In
LRP: X-12 Modified (Takes two 4x10x4) (Stock motor takes 4x11x4's)
Nosram: Pure Evolution (All) (Takes two 4x10x4)
METRIC: 4mm (Inner) x 10mm (Outer) x 4mm (Width)
STANDARD: 0.15748" (Inner) x 0.3937" (Outer) x 0.15748" (Width)