Xero C1 ProCAPTURE PRECISION. EXECUTE PERFECTION. The most essential data for ballistics calculations is projectile speed. A chronograph is the best tool for the job. Whether youre handloading for the range or building arrows for the hunt, the Xero C1 Pro chronograph provides the speed data you need to hone your craft. Measure projectile speeds from 100 fps to 5,000 fps The button operated design is simple to use Pair with the ShowView smartphone app to track