The Barrel Extender is for use with an ASV Clutch Lever Perch Setup (Standard or PRO) and takes the excess slack out of the clutch cable, which is experienced in some rare cases on certain applications.
Each order will include 2 Barrel Extenders.
My RMX 450Z was one of the rare instances that needed the excess slack in the clutch cable. ASV sent me a 2 pack free of charge. One sleeve did the trick. Now the church works perfectly.