Heart rate monitors
Bar mounted or wrist mounted, the "HRM" is a serious piece of kit. Once you know the basics, an HRM can vastly improve the way you exercise by logging your body's optimum performance levels, allowing you to make the most of your fitness. Many HRM's come with computer software so you can track your performance and share your results with friends and the online cycling community. If you are serious about improving your performance, an HRM is most likely your first stop!
Polar RCX5 Bike Heart rate monitor