E-commerce sales for 2017 were $453.5 billion in the U.S. and $1.1 trillion in China, an increase of 16.0% and 32.6% respectively over 2016. This upward trend is projected to continue for the next many years. Consequently flexibility and an ability to handle an ever-increasing number of parcels is of concern to warehousing, fulfillment and distribution center (DC) managers around the world. Handling, distribution, transport and delivery – and the amortization of facility setup charges which often represent more cost than raw materials and manufacturing combined – are part of mounting challenges faced by today's fulfillment executives. Accordingly, warehousing and material handling are a big business for hundreds of different types of companies that provide conveyors, rollers, racks, vision systems, hoists, shelving, electric motors, slides, barcode readers, printers, ladders, gantries, tugs, forklifts, skids, totes, carts, and software systems of all types.