Brand new fully-assembled bottom part of the Mobia machine (by Nautilus Bowflex) includes: Motor, power switch, walking belt, belt adjustment bolts, treadles, transport handle, levelers, side foot support platform, and transport wheels. Two (2) are available, and each can simply be connected to an existing Mobia machine or used as a spare part. Net weight: 116.8 lbs. Gross weight: 129.2 lbs. Volume: 10.47 cubic inch. Mobia combines 3 workouts in 1: Benefit of a treadmill, stair climber, and elliptical trainer. Mobia is efficient in burning calories without the pounding and joint pain from regular treadmills and stair steppers. Mobia burns calories twice as fast as a treadmill at the same speed. Please go to, http://walking.about.com/od/treadmillreviews/fr/nautilusmobia.htm , for more details on Mobia.