Cedar, bluebird viewing house, also includes a side viewing window to watch the hatchlings while keeping them safe, features maximum ventilation, elevated mesh base to manage blowflies, predator guards & fledgling skerfs, the naturally insect & rot resistant cedar has a water based preservative to maintain color longer & hinder mold & mildew growth, all hardware is rust free, approved by north American bluebird society by meeting or exceeding their standards, comes with a 5 year warranty.