Polystyrene National complete polyhive incl. Varroa tray and metal grid. 1 innercover (transparent plastic). 1 queen excluder (plastic). Polyhives is a newly devolped polystyrene hive made from high density polystyrene. Manufactured in Denmark specially for the British market. Polyhives are highly insulating, do not rot, have an improved interior climate which ensures a large honey harvest. Great advantages as compared with traditional wooden beehives. Compatible with National wood hives.