The service course sl 6 degree stem from zipp was first developed to meet the needs of the pros that goal of being pro grade has stood the test of time over the past several seasons as the stem became a mainstay in the pro peloton and cyclocross circuit being ridden to victory in paris roubaix and the vuelta a espana now zipp have built onto the legacy of the pro proven stem and redesigned it it is made from 7075 aluminium and features a new shape that is strong and lightweight with a best i