Convert your housing from round entrances to starling resistant crescent entrances with these aluminum plates. Crescent entrance hole measures 1 3/16 inch x 3 inch. The plate measures 5 inch wide x 6 inch high. Aluminum plates are best used on houses (plastic plates work best on gourds). Install plates with your choice of screws, bolts, or pop rivets (not included). Use requires enlarging original entrances, instructions included.