That is a Campbell Scale Models kit called Saez Sash and Door. This is the millhouse and chip storage loft. There is another kit that goes with it containing the lumber shed, overflow shed, machine shop and hopper. That is the kit I am building now. It will be stained the same way to look like it was built at the same time.Still to come are Keystone Locomotive Works Bandsaw Mill, Planing Mill and Kiln and SSltd Jennings Lumber and possibly a few more before I am done. The bandsaw mill, planing mill and Jennings Lumber all have detailed interiors as well. The millhouse features real cedar shingles on the chip storage loft and real glass in the windows which is really nice if you want to model any broken or cracked windows. Unfortunately I forgot to do that before I put the windows in. Ron.