The Eco-Safe Toilet System is designed to fit into a 20 mm rocketbox but can also be used as a stand alone toilet. Its cubical shape saves 20% of the space required by a round bucket type toilet system. The Eco-Safe Toilets Rocket Box System includes a 5.5 gal. tank, full sized comfortable seat with lid, washout kit for flushing, pressure relief vent, and buttress threaded, gasketed closures. The Eco-Safe Toilets Rocket Box System empties easily at an RV dump or in a Scat Machine. Meets BLM, NPS and USFS requirements. If you'd like to substitute "old style" seat please place order by phone (303-467-9489).