The internal dimensions of are Warré Brood Boxes are 300x300x210
Please Note: The walls of the brood box are 25mm thick, so the external dimensions are 350x350x210. If you require a thickness smaller than 25mm, please let us know and we can manufacture accordingly. Some manufacturers brood boxes are as thin as 19mm, this in our opinion is to thin, not only for insulation purposes , but for structural integrity. We will not manufacture less than 20mm, so please check your own boxes before ordering.