Perhaps signifying the device's popularity in the US, a book light company has launched a version of its Periscope range for the Amazon Kindle e-book reader.

The "Periscope Lighted Folio for Kindle" is a Kindle cover that also features a built-in retractable twin LED reading light, as well as notepad and pen holders.

Powered by three AAA batteries, offering 40 hours runtime, it's $49.95, available now.