ARMOUR39® MODULE. Stores your biometric info—including heart rate, calories burned, real-time intensity, and WILLpower™—and transmits it automatically in real time to the Armour39® App or Watch. Compatible only with iPhone® 5a, 5c, 5, 4s, and iPod Touch® (5th generation). Captures every heart beat so you get precise measurements no matter what you wear it to do. Using a Bluetooth connection, the Armour39® Module wirelessly transmits workout data in real-time when you"re within range of your iPhone or iPod touch; go out of range and it stores your workout data, automatically transmitting your info to your app when you"re back in range. Transmits within 15 feet of your display device (see above for compatible devices). Module is sweat proof (cannot be submerged in water). Long lasting coin cell battery is ready to go when you are. For questions, call our Armour39® Customer Service line at 1-855-901-3939. ARMOUR39® CHEST STRAP. Not just a strap...it actually performs; it wicks sweat and stays put thanks to. grippy Nano technology that keeps you comfortable and focused. Sensing pads detect the body"s biometric info and deliver it to the Module. Comfortably fits a ribcage measuring 27"-52" around (see models for fit). To clean, remove the Armour39® Module and hand wash. ARMOUR39® APP. Get every piece of vital workout info, all in real time in a single location. Use the calendar to compare your daily workouts and see how you"re improving over time and pinpoint trends. Stores 120 days. Compatible only with iPhone® 5a, 5c, 5, 4s, and iPod Touch® (5th generation).