This Bird Eviction Door is designed to let birds out of an entry point on a structure. Let birds remove themselves by installing the eviction door over the entry point with the included mounting tabs. Birds can easily push the clear acrylic door open but cannot push it in to gain re-entry. This eviction door measures 4" wide x 4" tall and is only 2" thick for easy placement even in tight areas. It is constructed of 1/2" x 1" - 14ga galvanized wire mesh and 1/8" thick clear acrylic.