This 10 frame metal queen exlcuder is made from galvanised iron with four sides bounded. It measures 51cm x 41cm - for a 10 frame box. The holes in the grid are perfectly designed to allow the worker bees through to the honey supers but not the queen.
Why use a queen excluder?
An excluder can be a helpful way to stop the queen accessing the honey supers in your hive. Many beekeepers prefer this method to others. The holes in this metal screen are only large enough to allow worker bees through to the honey supers and this stops the queen from laying her eggs in them. You want to keep the honey supers free of a brood developing otherwise it can be difficult to get clean honey when you harvest.