Japanese honeybee, for stacked boxes, iron four-sided entrance, for 240mm water collection basins. For stacked boxes of 29cm to 30cm square, and water collection basins with an outer dimension of up to 30.3cm square. (Also compatible with water collection basins with an outer dimension of 30cm) The entrance is 6mm and made of iron, so there is no need to worry about hornets biting it. The color is silver, but it can be changed to black upon request. Please let us know in the comment section after purchase. If you are considering a lifting machine when stacking boxes, we recommend an entrance compatible with a lifting machine. As it is handmade, there may be some distortion or uneven paint. Please refrain from purchasing if you are concerned about this. We are selling this to support Japanese honeybee beekeepers and to hope that the Japanese honeybee population will increase and the mountains and fields will become more vibrant. We hope it will be helpful to everyone. #JapaneseHoneybee #JapaneseHoneybee #FourSidedEntrance #StackedBoxes #Beekeeping #ConcreteBasin #InspectionBasin