The features of pick-to-light and put-to-light systems, which is in computer-driven, paperless warehouses and distribution centers, are discussed. The systems uses lights to identify pick locations and LED readouts to tell the order pickers the quantity required. The systems will increase order handling, productivity and accuracy. The reasons for finding majority of the pick- and put-to-light uses in distribution centers are speed in handling orders, very high pick or put accuracy rates, ready application to existing storage technologies, hands-free operation, and ease of training.