I researched them years ago. I wanted one until I learned it got too cold where I am in the winter… or so I seem to recall that was case.
Then, I found this other cool thing that you attach to your clean out. It’s like a big funnel with a lid. You “make a deposit,” then flush with a bucket of water. Turned out my clean out is located in a very conspicuous spot. It’s called the Doggie Doo Drain. https://www.amazon.com/Doggie-Doo-Drain-Waste-Attachment/dp/B0020N940C/ref=lp_8461727011_1_1?srs=8461727011&ie=UTF8&qid=1476233900&sr=8-1
