THIS IS THAT LITTLE PIECE THAT YOUR "U" BRAKE CABLE RUNS AROUND AND IS THEN FIXED TO YOUR BRAKE CABLE. NOT TO BE USED BY BRAKLESS RIDERS. CNC MACHINED FROM ALUMINUM HELPING YOU NOT HAVE ANY BRAKE FLEX. USES A 2.5MM HEX KEY TO ADJUST. LOOKS MUCH COOLER THAN THE STOCK CRAP.