Sun-Mar SpaceSaver Composting ToiletThe SpaceSaver composting toilet is a three chamber toilet designed specifically for situations where space is extremely limited. With the exception of the GTG, the SpaceSaver is Sun Mars smallest composting toilet. The SpaceSaver is designed to be used when you have tighter spaces. With a width of only 19 1 2 and depth of 23, even a closet or small corner can now be turned into a bathroom! Installations include, but are not limited to: cabins,