Smooth Fitness 6.45M Folding Treadmill with Music Kit Deluxe sound system - attach your ipod/mp3 player, cd player or other audio device to the auxiliary input jack Patented swing arm shock absorption - the patented suspension running deck is proven to lessen the impact of walking and running Gas shock-assist lift you can gently tilt the deck into position and wheel it away for storage Engineered with an advanced pulse Width Modulation (PWM) circuit board more typically found on commercial treadmills Lifetime warranty on the frame and motor; 5-year warranty on all parts and one year of in-home service