CAT EYE - Bluetooth Heart Rate Sensor Kit TRAIN SMARTER: Track your heart rate to push yourself further and achieve your fitness goals. Get ready to train harder and smarter. COMFORTABLE: The sensor snaps onto a comfortable fabric strap that lets you ride without distraction. COMPATIBILE: This kit is compatible with all Bluetooth Smart cycling computers, watches, and smart phones that record heart rate. STAY IN THE ZONE: Don't sweat it! The chest strap is water and sweat-resistant, but we recommend hand washing it regularly. It fits chest sizes 25-55 inches. GO THE DISTANCE: With a battery life up to 4 months (1 hour of use per day), you can install it and forget about it.