Pallets are stored 3 or more deep on the rails and goods are deposited and retrieved by forklifts actually entering the rack structure. 

Several levels can be employed in the height with rails serving to separate the different levels of pallets and so preventing load crushing in what is virtually a block stacking situation. 

Access aisles are restricted to those serving the face of each block, making the system highly efficient in its use of space. 

The technique allows only limited rotation of stock, making it most suitable for storing homogenous products, where turnover or direct access is not a decisive factor.