The Wahoo RFLKT+ Smart Bike Computer: an iPhone powered bike computer that connects your iPhone wirelessly to ANT+ cycling sensors

1) ANT+ connectivity: you can now connect ANT+ sensors like your power meter, heart rate strap, and in-frame sensors directly to your iPhone. The RFLKT+ takes the ANT+ signal and converts it to Bluetooth Smart (aka Bluetooth Low Energy or Bluetooth 4.0) so the iPhone can read the data and display/store it in the App.

2) A barometric altimeter. Accurate elevation data is key to any cyclist.