Things are BASED as Hell. Mass acts like a heat battery , slowly releasing heat into your House, Cabin, RV, Shed to house, whatever. It uses about 85% less wood, you get Heat obviously, can cook on top of 55 gal drum, and can heat water on top. I seen videos of people adding copper coil and copper pipes around it and had an off grid water heater attached, pumped out hot water. Have you heard of them? I know from experience, these things can and will save your Ass in a dire situation if finances should screw you over and you need bare minimum to off grid and save money. Great invention.