A Kiva robot moves a rack of merchandise at an Amazon fulfilment center on 20 January2015 in Tracy, California. Getty Remember Kiva Systems?

It's the company Amazon bought for $775 million in 2012. Kiva makes robots that automate the whole picking and packing process at large warehouses.

Amazon began using Kiva robots only last year, and by the end of 2014, said it had 15,000 bots working across 10 of its warehouses.

Now it looks like Amazon's using the Kiva robots a lot more widely, according to its earnings call that just ended now.

"We are up to 30,000 bots at the end of Q3, and in the 13th fulfillment center," Phil Hardin, Amazon's director of investor relations said during the call. "Our intent is to use that more widely, so stay tuned."

When Amazon acquired Kiva, it was expected that the robots would significantly improve Amazon's packing and shipping efficiency. Hardin said the wider use of robots at fulfillment centers had a direct impact on its productivity.

"It’s a bit of an investment that has implications for a lot of elements of our cost structure, but we’re happy with Kiva," Hardin continued. "It has been a great innovation for us, and we think it makes the warehouse jobs better, and we think it makes our warehouses more productive.”

In case you haven't seen the Kiva robot, it's a square-shaped, yellow machine that runs on wheels. They're about 16 inches tall and weighs almost 320 pounds. They can run at a steady 5 mph and haul packages weighing up to 700 pounds.

The video below gives a good look at how it works at Amazon's warehouse facilities: