The Pro Nuc is a sturdy recyclable plastic tote with lid that firmly latches and doesn't let bees escape. Drain holes in the bottom lets moisture out. Stops on the frame rest and retainers in the lid, keep frames in place and prevents them from sliding and banging into each other. Two feeding options on the lid: 1) use standard soda bottle. 2) built in detail for hive-top feeding. Provides plenty of ventilation for full nucs.