Locking Shaft Collar. Complete with Set Screws.   
 
Dimensions and Specifications:
ID                   7/8"
OD                 1-31/64"
Height            9/16"
 
Billy Jack's Inc. has been an authorized Rotary dealer for
over 30 years selling high quality parts at reasonable 
prices.  Our goal is 100% customer satisfaction.
Thanks for looking.