This pack contains everything you need to transform your iPhone into a training computer. 

Plug the Ant+ key from Wahoo Fitness and put the heart rate belt for iPhone from Wahoo Fitness on. Launch your preferred application (RunKeeper, 321Run, RunMeter, Runtastic, MapMyRun and others) and view, listen, record and analyze your heart rate while running. This key connects to yo your heart rate monitor belt for iPhone.

The heart rate belt is the high quality belt from Wahoo Fitness: 

• comfortable, elastic fabric strap to minimize chance of chaffing. strap can be hand washed
• accurate and reliable, records data even when receiver communication is interrupted
• two-snap connection is easy and fast and includes adjustable length strap
• sends and receives signals up to 10 feet
  
• compatible with any ANT+ receiving device
• waterproof up to 5 feet
• replaceable 3 volt CR2032 coin cell battery

The Wahoo key enables the communication between your heart rate belt and your iPhone app: 

• very low power usage, no internal battery
• compact, similar size to iPhone charging plug
• compatible with iPhone 3G, 3GS, 4, 4S, iPod touch, iPad 1 & 2, fits into Apple proprietary 30-pin connector

These two devices are "Made for iPhone".

Different applications have different features. All use the precise, light and sturdy combination of Wahoo Fitness belt and Key. The ANT+ wahoo key is also compatible with other belts that wear the ANT+ logo (Garmin, Timex,…).