17mm ID x .9" wide, 1.375 x 24 RH, 4mm keyway, 2 set screws. Freewheel Sprocket Adaptor

NOTE:  If you need the larger 6mm keyway, select the link below.

Click Here for the 17mm adaptor with the larger 6mm Keyway

CNC machined out of 12L14 steel for the single, dual or multi speed freewheels.

To find all the types & sizes of adapters - adapter - adaptor - Track Cogs - Lock Rings - Track Cog & Three Prong Sprockets: 

Type " FWADP " in the Search box.