Selling fuel stove.
Selling carbon technical.
It is possible to supply on a continuous basis in any quantity.
Fuel unlike oil, does not require pre-heating, even in winter. Is a qualitative analogue of mazut M100, surpassing it in their characteristics and properties – no need to warm up in the winter, produces more than 25-30% of heat energy.
Carbon also is used as a fuel, but cheaper than coal.