A modern tool with many advantages... • Double walled with the gap filled with polyurethane foam insulation. • With 2 ventilation plugs • Unmatched impact strength and load support. • Anti-slip surface to prevent hives from slipping during transportation. • 4 points of attachment at the front, back and the sides (adjustable or wire type). • Resistant to chemicals (caustic potash, oxalic acid, formic acid, bleach etc.). If you use ventilated bottom boards the hive has adequate ventilation even without ventilation caps. Just think of the wild hives settling on the top part of closed spaces, like tree hollows.