National Frame Feeder for an Extra Deep box, Jumbo 14x12
Not just for feeding - these provide excellent insulation especially when filled with sheepswool.
This fits in the hive in place of a frame
These are 35mm at their widest, the standard spacing for brood combs so they will fit exactly in place of a Hoffman brood frame.
All wood construction, untreated woodwork will need an application of wax/oil/glue/paint to seal before use.