What you get: 18 copper entrance guards and 72 matching screws — enough to outfit or multiple birdhouses and to share extras with friends. Material and durability: Made from copper for longterm use. The metal is rustresistant and sturdy, providing reliable protection for birdhouse entrances. Size and compatibility: Each guard measures approximately 5 x 5 cm (2 x 2 inch) with a 1 1/2 inch diameter opening. The portal size fits most birdhouses and is specifically suitable for eastern bluebird houses. Primary function: Reinforces and protects the entrance hole of a birdhouse, reducing wear and preventing enlargement of the opening while maintaining a clean, consistent entry size for nesting birds. Easy installation: Align the guard opening with the birdhouse entrance, then tighten the four corner screws (included) to fasten the guard securely. Performance highlights: Corrosionresistant copper maintains appearance and function outdoors; included screws provide a complete installation kit so you can install multiple guards without buying hardware separately. Practical use scenarios build: Add to newly built birdhouses to protect the entrance from pecking and weather right away. and maintenance: worn or enlarged entrance portals on existing birdhouses to restore the correct hole size for cavitynesting species. Backyard habitat management: Install on multiple boxes around a property to give consistent, protected entry points for eastern bluebirds and other compatible species. Product notes Quantity: 18 guards, 72 screws. Dimensions: 5 x 5 cm (2 x 2 inch) per guard; 1 1/2 inch diameter opening. Compatible with most standard birdhouses; recommended for eastern bluebird houses. Installation requires aligning the guard and fastening the four corner screws (all screws included).