Nokia's Lumia 2520 with the Power Keyboard.

Owners of Nokia's Lumia 2520 tablet who missed out on the free Power Keyboard can now buy one through Microsoft.

Packing in a case, keyboard, two USB ports, and a 50 percent boost to battery life, the Power Keyboard was dangled by Nokia as a free accessory to those who preordered the 2520 late last year. AT&T has been selling the keyboard, and now Microsoft has added the $149 device to its lineup.

The Power Keyboard sold by Microsoft supports only the Lumia 2520 through AT&T, which means Verizon customers are out of luck. The keyboard currently shows up as out of stock through AT&T, both online and at many of its retail outlets, so Microsoft seems the only source for now.