Sale is for one 10 frame Langstroth custom Honey Bee Hive Insulated Vented top board for colony overwintering success. Losing hives over winter on a continuous basis for years, year after year like me? Not any more! Finally decided to offer these after actual testing for the past several years and can almost guarantee your bees will survive winter using this item. Just a warning you may need a bucket loader for honey collection in the future after using. It’s confirmed after using this 1″ insulation board for several years now, it will increase overwintering honeybee success by at least 100%. Hives without this insulated vented top board have little to no chance of surviving a northern climate winter. The heat from bees creates condensation at top that drips down and kills them. Even an absorbent top board is not enough. This vented insulation board stops the condensation and your bees will survive winter. You won’t find this idea in a book anywhere. This goes between the inner cover and outer cover with the slot facing down for bees to come and go plus provides top vent. It only took me 25 years to figure this out, it works!