The Polar 520 was designed for the ultimate crosstrainer or triathlete. The added cycling features let you track performance in all disciplines. The new distance based interval function helps guide you through your toughest workouts on the bike. With the Sonic Link technology and the new advanced PPP 4.0 software, you can download your heart rate and cycling data, as well as maintain a training log and even share your data through email. Swim..Bike Run..Download. New dual position bike mount included. The S520 features a new lightweight stainless steel design for added durability.