Horizontal carousels are shelving rotating on a track. Carousels deliver parts to the operator instead of the picker walking to the location, and combined with software and pick-to-light, allow a single operator to pick multiple (typically between 8-16) orders in a single picking batch. Because there are 2-4 carousels per pod, when the operator is picking an item from one carousel, the adjacent carousels automatically preposition for the next pick to eliminate waiting. Carousel technology allows a single operator to accurately complete hundreds of item transactions per hour in a fraction of the space of shelving.