DX3 Belt and Deck System. Conveniently places the most-used controls right at the user's fingertips.. The patented Lifepulse digital heart rate monitoring system, including contact hand sensors, provides heart rate monitoring with exact precision; Polar telemetry provides accurate, “hands-free” heart rate monitoring.. Stride Sensor Detects when a user leaves the machine and stops the belt after a brief delay.. Remove the two large cup holders for easy cleaning..