5x11x4 MR115ZZ Halo bearing by Avid Racing Concepts is a popular bearing for 8th scale buggies like the Losi 8ight, Kyosho MP9, and Hot Bodies D8 as well as many helicopters.
Bearing Dimensions
METRIC: 5mm (Inner) x 11mm (Outer) x 4mm (Width)
STANDARD: 0.19685" (Inner) x 0.43307" (Outer) x 0.15748" (Width)