Merc V-7 Commercial AC Treadmill IFxThe Merc V7 commercial treadmill is a revolutionary new running experience. At its heart is the patented Flex Deck System, featuring an aluminum deck supported by a hexagonal polymer suspension system. Runners experience an unprecedented cushion and responsiveness described by users as easy on the joints and like running on a track. Automatic incline 20% Safety lock Have Shock Absorber System Inside the machine Headphone Jack 3. 5 mm Size machine