This unit can be added to your existing martin house to grow with the colony that inhabits your current martin house. Does not include roof pieces, but does include door stops and protective rails. Constructed of tough, lightweight aluminum. Hexagon shape is compatible with the model No. AH12D all aluminum martin house in your RSC. Some assembly required. Assembled dimensions: 26.5" W. x 20" H. x 26.5" D. Color: Green roof and floor with white walls.