The Compact is a sleek, low-profile unit that will complement any bathroom. Sun-Mar engineers created this low-profile toilet by developing a new variable diameter bio-drum that is small in the front and large in the back. To maintain the Compact's uninterrupted lines, a patented bio-drum handle is machined into the body of the unit to mix and aerate the compost. The Compact differs from the Excel in that all three chambers are smaller, making the Compact ideal for light residential or light to medium-duty cottages. Like the Excel, a 2" vent stack attaches to the back of the Compact. A 1/2" emergency drain on the back provides protection in the event of heavy or residential use or extended power outages.