Made from Weserrn Red Cedar - so no need to paint or treat and will last up to 40 years outside. Made from 3/4" / 20mm thick timber - giving better insulation for the bats from the weather. Screwed and glued to keep out the drafts. Double chamber. Dimensions: 520mm x 1130 x 140mm (18mm x 90mm entrance). Designed with top and bottom fixing holes. Siting and care instructions included.