Precor TRM 425 Precision Series Treadmill Integrated Foot plant Technology reduces stress on knees, ankles and hips by adjusting the belt speed to match the natural movement of your feet Patented Ground Effects Impact Control technology uses precisely engineered shock absorbers to provide the perfect amount of cushioning 10 preset workouts help you stay challenged; built-in warm up and cool down periods Treadmill deck adjusts from +15% incline to -2% decline to simulate the ultimate in terrain variety Touch sensor and wireless heart rate monitoring; works with any Polar-compatible wireless heart rate transmitter (sold separately)