This is a great nest box from Gardman as it has been designed to offer you great flexibility. You get the choice of either a 32mm hole that is suitable for the house sparrow and the Nuthatch, or a 28mm hole which will suit the Great Tit, Blue Tit and the Tree Sparrow. or by removing the front all together you will attract Robins, Wren's, Blackbirds and Pied Wagtails. The construction is very solid and it is made with FSC certified timber. The instructions are easy to read so go on treat your garden birds to somewhere nice this breeding season.