1) Vertical lift module
A Vertical Lift Module, or VLM is a storage system that consists of two parallel columns each of which is divided into fixed shelf locations that can hold a single storage module such as a tray or tote. The shelving locations are single deep. A tray or tote is inserted, extracted and transported between storage levels and picking locations via an elevator-like device with an automatic shuttle that travels up and down within the space between the storage columns. See also Carousels and/or AS/RS .