The MSC-2Dx is the latest in Heart Rate monitor and cyclocomputer integration. Up to 42 hours of heart rate and speed data can be captured internally on a memory chip. This can be replayed manually or downloaded to a personal computer for comprehensive evaluation. Four programmable heart rate zones offer tremendous advantages to athletes in training on or off the bike. Audible alarms, waterproof design and user-replaceable batteries in the main unit and chest strap make the unit practical to use and maintain.