The SREH (starling resistant entrance hole) is a tried and proven method for helping to eliminate the pesky European Starling. Tests have shown the entry holes are 99.8% effective in achieving this. This hole is cut to an exact height restricting starling entry but allowing safe entry for the Purple Martin which gives it a greater sense of security. The SREH Mansions come with all cool aluminum and stainless steel construction, reflective roof, ceiling panel for proper ventilation, porch dividers, hinged clean out doors, guard rails, top perch, and an all aluminum base plate. Each room 6" x 6". Assembly Required. Door plugs sold separate. Dimensions: 14-1/4" W x 19" D x 15" H. By Birds Choice.