These reducers will fit either 8 or 10 frame hives due to their sliding adjustable design. They are constructed from two pieces of 24 gauge steel with a baked on enamel finish and are peppered with 3/8" holes for the bees to enter and keep the mice out.
These are the go-to for their adaptability and simplicity of installation. They can be trusted to keep out mice and assist new packages, and they are easy to sanitize for use in different colonies. If a design improvement were to be made to these I would hope that it is the shape of the holes; it seems that the undertakers have difficulty taking dead bees out through them with the same speed that they would on the classic entrance reducer design.
Meta Universal entrance reducer
Excellent simple design lets me protect against mouse invasion and reducing the possibility of robbing. These reducers will last for years to come.