The BCW Card Bin is a premium version of the cardboard, 4-row Monster Box. Instead of corrugated cardboard, Card Bins are made from durable, acid-free plastic. Card Bins have a pair of hinged lids that tuck under the bins when open. When closed, latches keep the lids shut and cards secure. Card Bins are stackable with feet on the bottom that rest in the lid of the bin below it to prevent sliding. The rows in the bins are notched along the top to hold separating partitions. Four Card Bin Partitions come with each Card Bin while extra partitions may be purchased separately. The card bin also comes with a set of BCW toploaders that fit into special, exterior slots to help mark the contents of each row.Additional Card Bin Partitions are available separately.