logwood boiler made in Richford, NY. Two sizes, I had the three foot long firebox x 18" wide and a shaker gr8 on the whole thing . I filled in half of the bottom with fire brick in an angle iron cage to reduce the size. The thing burned great but was just to big. I used to place one piece of hardwood in the center an pile coal on both sides , the wood kept air in the middle and I rarely had any trouble. But ......it wasnt a stoker and i could never go back. I think the large unit is around 5k and could easily put out 200k btu. smaller one around 4k and 125k btu. extremely well built.