Suunto is the world #2 in heart-rate monitor technology. Suunto manufacture a range of different handheld and wearable computers and supply GPS & navigation devices to the US military. All Suunto heart rate devices come in 2 parts;

• the wrist watch (which receives the signal and displays your heart rate and other useful data)
• the transmitter (in every case, this includes a wireless chest-strap to transmit your heart-rate, but for some models, can also include a foot transmitter and/or a GPS transmitter to  communicate speed etc.)