Number 4. My #HeartRateMonitor. If I could advice people to get one single piece of equipment as an exercise companion, it would be a heart rate monitor with Bluetooth/ant+ connectivity (provided the person has a compatible device). Even the best one, the #PolarH10, is under 100 USD. My training has never felt more precise and I’ve never felt more conscious of my fitness since I got it. Plus it connects to everything! The Erg. My phone. The bicycle computer. It’s incredible