It looks like Amazon may have a sleeper in its hands, and it’s not the more highly-regarded 7-inch Kindle Fire HD. According to the Amazon website, the online retailer’s new monochrome e-reader, the Kindle Paperwhite, has officially sold out.

As of the new 6-inch device’s October 1 release date, pre-orders were still being accepted on the Amazon website, although customers were advised that if they order now, they would have to wait 3-4 weeks for their devices to arrive.

That has since been amended to 4-6 weeks following the announcement. So if you order a Kindle Paperwhite today, there’s a good chance you may be receiving it about a week before Thanksgiving at the latest.

A lot of these Paperwhite sales may have been driven by positive reviews on tech websites; some of them have, in fact, referred to it as the best e-reader ever manufactured. Retailers have also been quite receptive of the e-reader upon its release. Despite this obvious sign that the Paperwhite has been an amazing success thus far, we don’t expect Amazon to release official sales figures anytime soon.

Amazon has been known for being very tight-lipped on sales of its devices and their respective market shares.

The Kindle Paperwhite has mostly been praised for its higher resolution and improved readability in well-lit and dimly-lit areas alike. The user interface has become much smoother as well, with little to no lag time.

However, the Kindle Paperwhite, like Amazon’s other recently-launched devices, comes with “Amazon special offers”, advertisements that can only be removed through a one-time $20 opt-out fee.