Custom built by us here at the Source. One of the best racing wheelset we have every built these wheels are built around Onyx patented sprag clutch mechanism which gives you instant engagement when pedaling and instant disengagement coasting for less drag. The wheels have been topped of with Stay Strong V3 pro carbon rims with double butted Halos spokes to make them super light and saving on that rotaion weight! This version comes with 20mm front hub and 10mm rear with disc mounts.