The 1.5x4x2 metal series of bearings are a high quality steel/chrome bearing with metal shields. These bearings have been tested and proven by many racers. Please check your manual to see if these are bearings you need to use.
Bearing Dimensions
METRIC: 1.5mm (Inner) x 4mm (Outer) x 2mm (Width)
STANDARD: 0.05906" (Inner) x 0.15748" (Outer) x 0.07874" (Width)