The Excel is a high capacity Bio-drum toilet that is very simple to operate, features well proven technology and is extremely reliable. The Excel was the first ever self-contained composting toilet to be certified by the National Sanitation Foundation (NSF). The Excel has enough capacity that it can be used just about anywhere; in residences, cottages and even in light commercial applications. The 2" vent is attached at the top back of the Excel and can be installed invisibly by running it through the wall and up the outside wall. For comfort the Excel has a sturdy detachable footrest which can be removed to pull out the finishing drawer. In normal use the Excel can normally evaporate all liquids, however a ½" emergency drain is fitted at the rear and this should be connected if the unit is to be used residentially or heavily, or if prolonged power outages are expected. Composting capacity: 3-4 Residential, 6-8 Weekend and Vacation Use. Color: White Please call for accurate shipping quote.