Amazon has designed a futuristic wristband that tracks workers movements across its sprawling warehouses and alerts them when it is time for a break.
The device - which resembles a smartwatch without a clock face - could be used to "monitor performance of assigned tasks", according to an Amazon patent filing.
The ultrasonic bracelet alerts a worker to a shelf where a package for the order they are completing, before sending it out for delivery. Correlating ultrasonic devices would need to be placed around the warehouse to be picked up by the bracelet, all powered by a powerful data-crunching tool.
The bracelet could buzz to alert the wearer that it is time for a break, or to clock off.
Amazon is renowned for its creative approach to packaging and shipping the 26million items it sells daily. Most notable is its plans for a drone-based Prime Air delivery service, which could deliver orders to a customers' door within half an hour and has already been tested in the UK.
Other inventions, which have yet to come to fruition, include nine-storey beehives to use as drone delivery centres. The high-rises are designed to save space and would feature landing pads
It has designed flying warehouses which would dispatch drones to customers' homes while in motion.
The flying warehouses, as detailed in a patent filing, appear like blimps and soar 45,000ft above cities, unleashing drones to fly the last stretch to a customers' door.
Amazon has led much of its airborne delivery testing from the UK, where special permissions from the Civil Aviation Authority have made it easier to run the pilot.
Amazon has more than a dozen large warehouses in the UK, which it refers to as "fulfillment centres".