Snow safe - this protection helps prevent the entrance hole from being enlarged to access young birds Flight hole adjustment - the protective plate design allows the flight hole diameter to be adjusted for different bird species Easy to install - with 6 included galvanized screws, the sheet can be installed in minutes Weather-resistant - the aluminum sheet is durable due to its natural oxide layer Color: Silver Material: Aluminum Package Contents: 2 x Heart-shaped birdhouse protection plates (1 x 28mm orifice plate + 1 x 32mm orifice plate) 6 x Screws Only the above package content; other products are not included Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the real thing. Measurement allowed error is +/- 1-3 cm