Wahoo Fitness ANT+ Plastic Heart Rate Strap for iPod touch, iPhone, and iPad Compatible with popular iOS Apps: RunMeter and Runkeeper MapMyRun and Runtastic Endomondo,CycleMeter,MapMyRide,Cyctastic Endomondo and Strava Designed to hold iPhone 3, 3GS, 4, 4S, iPod Touch 3, 4 with the Wahoo Key attached (not included) Weather and Sweat-Proof; thick neoprene band cinches snugly to your arm to minimize bouncing and chaffing issues Soft and Comfortable; Fits up to 14 inch arm (355 mm) Side headphone port keeps sweat/rain from getting into your iPhone (headphones not included) Features a Velcro holder for your excess headphone cord