Set of 2 6303ZZ double shielded scooter wheel bearings. Also commonly referred to as 6303Z series.
Shielded (ZZ or Z suffix) scooter bearings of this size are commonly used in wheels, transmissions, gearboxes, and various other GY6/QMB139 engine components.
These single-row, deep groove ball bearings are designated as medium-weight and feature a 17 mm diameter bore hole.
Be sure to check your existing bearings for the series number, which is often etched onto the outside wall of the bearing.
Diameter (Outer): 47 mm
Diameter (Inner): 17 mm
Width: 14 mm