The Wahoo Tickr X is a heart rate sensor that was used by team Sky in the recent Tour de France 2016 stages (in the Pyrenees, the jerseys are wide open).
The Tickr X is Wahoo’s flagship heart rate monitor featuring dual band ANT+ and Bluetooth 4.0 wireless capabilities. The build-in memory can record up to 16 hours of training. The Wahoo Tickr X can be connected to almost every iPhone or Android smartphone, but also a wide range of tablets and ANT+ enabled devices like for example cycling computers.
Personally I use the Wahoo Tickr X in combination with my Pioneer Pedaling Monitor System (SGX-CA 500 computer and SGY-910HL power meter).