Clean Wood Treatment: the use of untreated and breathable wood ensures balanced temperature conditions inside the nest box A nest box for black swifts, birds that live mainly in urban areas and nest high up Superior quality Dimensions: Height: 19cm / 17.5cm Total height (with rail): 28.5 Width: 38cm Depth: 21cm Hole: 3.2 / 6cm Assembly method: staples and 40mm screws Color: natural wood