Dia-Compe AD999 Proper Bike Co CNC Brake The lightest caliper available!... Dia-Compe AD999 Dia-Compes new top end caliper. The AD999 is a fully CNC machined version of the classic BMX U-brake... Super S*** U-Brake Super S***'s U-Brake is a low profile, 6061-T6 forged caliper brake... Linear Brake Cables: The linear uses a specially braided outer cable which allows you to wind up your bars...