This is the O Scale Yard Office Kit (5-1/2 x 4 x 5-1/2'') from American Model Builders.
Designed for ease of construction, all Laserkit structures feature precision laser-cut basswood and plywood parts that assemble much like plastic kits. Unless noted, all kits feature peel-and-stick assembly windows with positionable sashes, doors, trim and roofing material. All walls and major assemblies have tab-and-slot construction. Kits may also include white metal and acrylic detail parts.
Based on a Boston & Maine design, 100% laser-cut wood with a wonderful rear staircase.