Spare toilet box. Does not come with seat or hardware.
Designed and tested in our own shop.... well, not tested in the shop, but well tested. The box seals with a large screw on lid on the top side. The poly boxes don't retain odors, and the compact size of the box makes it easy to rig in most boats. The wide base makes for a stable area of operations. A 3 in. drain plug and a 3/4 in. hose fitting are welded into the box. 50 user waste days.