The basic concept of SQS is based on the serving of bin racks by aisle-bound vehicles, which can retrieve and store up to four bins simultaneously using a special extracting device.

Due to the high dynamics of high-perfomance drive and control technologies, the combination of several units in the relevat aisles leads to a high throughput and minimum handling times and - in connection with the narrow arrangement of the bins which is now possible in the racks - to a minimun utilization of the existing space.