WildBird Care Hanging Birdhouse Painted Wood Camper Trailer House (02) Rust-proof hanger: steel wire strand inside and vinyl coated, ready to hang; Small-sized entrance hole: Small-sized entrance hole: 1 1/3 inch, large enough for wrens but small enough to keep larger birds/squirrels away; Openable door: for easy loading food and cleaning; Hand-painted with non-toxic, water-proof paint, no harm to yor lovely birds; Four wheel: really run! perfect gift for bird lover or lovely kids.