I did order one of these for an outside garage at one of my properties. I do love my Axis on demand so won't be taking in rig. Runs 2 D batteries and LP bottle. Have not seen this type of unit before. Thought I would throw it out there, could have lots of uses for the price.
Tankless Water Heater, GASLAND Outdoors Propane Water Heater 10L BS264 2.64GPM, Portable Hot Water Heater for Cabin, Camp Water Heater for RV, Overheating Protection, Easy to Install, White
https://www.amazon.com/dp/B078MHC2NF..._7MymEb604NTBB