Through shelves: is a not to channel segmentation, continuous whole shelf; rack through the tray access mode, used to store a single species, compared to large quantities of goods; and the tray shelf, warehouse utilization rate can reach about 80%, warehouse space utilization rate can be increased by more than 30% is storage efficiency highest shelves. In support of the guide rail, the tray storage according to the depth direction, one after another. Investment cost is relatively low, applicable to the lateral size larger, less variety, quantity that is often used to store a large number of the same type of goods, due to its storage density high on the ground space using rate is high, commonly used in the storage space of the refrigerator, food, tobacco and other high cost of warehouse.