Collapsible Storage box with lid which folds flat when not in use. Has 4 built in wheels on the bottom allowing the box to be easily moved. Easy stacking system-There are four grooves in the top lid to match with the wheels so the boxes lock in place. The folding storage bin can open either from the top or using the 2 front doors. The front door has built in locking handles, which ensures the doors don't come open on their own.