About Sigma Heart Rate Monitors: All Sigma heart rate monitors facilitate training in target zones, featuring pulse monitor, 12/24 hour clock, 5-year warranty and are waterproof to 3 meters. Fit, PC-15 and PC-9 have a Training Manager which monitors, plans and evaluates all workout data for up to 7 workouts, an Exercise Zone feature which calculates ideal personal training limits and 1-3 manually adjustable heart rate limits (including Shape model), 5 languages. PC15 also has an alarm clock, lap counter and back light. Nordic can mount to pole, bike or lanyard with adjustable head unit angle. Exclusive to Fit watch are the Fit-Test (a walking test to establish fitness level), adjustable contrast display and 7 memory slots.