Weldahub W 1/2" ID Round OD is 1.625" or 41.28 mm

Weldahub W 1/2" ID Round 000200085. 

Has a 3/16" keyway and 2 set screws, OD is 1.625" or 41.28 mm . 

Fits the 35 A Weldasprockets and the 41 A Weldasprockets (except for the 41 A 12, 13, 14, and 15 tooth).
Weight: 0.95 lbs