Bearings
Model: R188ZZ

Inner diameter (d): 6.35 mm
Outer diameter (D): 12.7 mm
Width (B): 4.763 mm
inch:
Inner diameter (d): 1/4 = 0.25 inches
Outside diameter (D): 1/2 = 0.5 inches
Width (B): 3/16 = 0.1875 inches
Accuracy grade: ABEC-7
Bearing Type: Ball Bearing
Bearing material GCr15 bearing steel
Ball material: GCr15 bearing steel

Lubrication: Grease lubrication
Bearing type: Ball bearing
Application: Electric nail drill bearings...