4 DIFFERENT SIZES : The Storage boxes come in 4 different sizesSMALL - LxWxH - 40.5 x 29.5 x 22.5 cm MEDIUM - LxWxH - 52.5 x 36 x 28.5 cm LARGE - LxWxH - 61.5 x 42 x 33.5 cm EXTRA LARGE - LxWxH - 67.5 x 47 x 36 cmCOLLAPSIBLE AND STACKABLE : The storage boxes and lids come in collapsed/ folded manner. The 4 sides of the storage box have to be raised and secured with the white rectangular panel provided. Close it with the lid to get the storage box ready for use. Please refer to the video below for guidance.5 SIDES OPENING : The storage boxes has 4 doors, 1 door on each side and a top lid. Use the doors to access and remove items in the storage box when it is stacked.DETACHABLE WHEELS : All storage boxes come with 4 black wheels which can be installed easily as shown in video below. Only the 4 layer storage boxes in size Large and Extra Large come with 360° rotating white wheels.CONVERTIBLE TO TROLLEY : All the storage boxes in any number of layers you select, come with lids. They can be stacked as individual boxes on top of one another or can be converted into a trolley. To convert it into a trolley, remove the lids of all bottom layer storage boxes, stack the next layer and lock the sides with the locks provided on both sides of the storage box. Only for the topmost layer close the box with the lid provided. Refer to the video provided below for further guidance.CALL US ON +91 8754940283 FOR FURTHER ASSISTANCE.