Amazon.com today unveiled its eighth generation fulfillment center, which utilizes robotics, Kiva technology, vision systems and other software and mechanical technologies to fulfill holiday orders. The company is currently operating 10 of this new generation of fulfillment centers across the U.S.

The orange 145 kg robots, which scoot around the floor on wheels, show how Amazon has adopted technology developed by Kiva Systems, a robotics company it bought for $775 million in 2012.

Each of the machines can slide under and then lift a stack of shelves that's four feet wide and holds up to 750 pounds of merchandise. The system uses bar codes to track which items are on each shelf, so a robot can fetch the right shelves for each worker as orders come in.

"The Amazon fulfillment teams are dedicated to innovating in our fulfillment centers to increase speed of delivery while enabling greater local selection at lower costs for our customers. The advancements in our latest fulfillment centers hit all three of these customer desires while continuing to provide a work environment that is great for employees," said Dave Clark, Amazon’s senior vice president of worldwide operations and customer service.

Amazon’s eighth generation fulfillment center include the Robo-Stow, one of world's largest robotic arms moving large quantities of inventory for customer order fulfillment.

New vision systems enable the unloading and receipt of an entire trailer of inventory in as little as 30 minutes instead of hours, Amazon says.

The Kiva robots have allowed Amazon to hold about 50 percent more items and shorten the time it takes to offer same-day delivery in several areas, said Dave Clark, senior vice president of worldwide operations and customer services.