Zipp Service Course SL-70 Drop Handlebar - Aluminum 31.8mm 36cm Matte BLK B2Zipp Service Course SL 70 Drop Handlebar Aluminum 31. 8mm 36cm Matte Black B2. The Service Course SL 70 is the bike fitters go to bar. The short reach to the hoods allows a proper fit without compromising stem length and steering control. With the revised ramp angle proper fit is now achievable on even the most challenging setups. Contoured top bar for natural ergonomic grip Internal cable routing Aluminum 7050 construction Compatible with clip ons