Our three Aluminum reducing bushing adapters set for 1-inch wide bench grinding wheels are with 3/4'',5/8'',1'' Arbor hole diameter, they have accurate dimensions with size#1: ID 1/2''x OD 5/8'' x H1'';#2: ID 5/8''xOD 3/4'' x H1'';#3: ID 3/4''x OD 1'' x H1''. Based on our intimate service, please contact us if you have any questions about our grinding wheel bushing or if you have recieved it with any flaw.