Wahoo Fitness wirelessly connects your iPhone 3G iPhone 3GS or iPhone 4 to your favourite fitness measuring devices including your heart rate sensor. With the Wahoo Bike Case your phone your favorite playlists the best fitness Apps and real-time activity information are all in the palm of your hand... or mounted on your bike Details: Built in ANT+ radio transceiver with support for all current and future ANT+ sensors Fits iPhone 3G 3GS and 4. Ships with custom rubber liners to easily adapt between phone types Wahoo Fitness Powered supported by most of the leading iPhone fitness Apps Water and shock resistant Bike mount with quick release for Case/semi-permanent mount attachment to bike. Adjustable portrait or landscape orientation MicroUSB port for charging/data connection with tethered rubber plug when not in use Fully accessible/functional touch screen access Universal mounting rail for bicycle mount and auxiliary battery. Optional auxiliary battery (soon to be released) Wahoo Fitness rail mounted 2.3 AmpHour battery (1.5x that of the iPhone battery) or any auxiliary battery with microUSB plug compatible sends and receives signals up to 10 feet unobstructed