Microsoft has been promising power covers for its Surface 2, Surface Pro and Surface Pro 2 for about six months, but until now we had no idea when they were actually going to hit the market. The company recently posted a pre-order page for its Surface Power Cover, which will start shipping on March 19 and is available for $199.99. That price includes free shipping, and if you decide you don't like the Power Cover you can send it back free of charge.

The Surface Power Cover  is only available in black and adds an additional half pound to the weight of your tablet. However, it measures just 9.75mm thick and offers a full QWERTY keyboard with function controls, dedicated Windows shortcut and media controls and an accelerometer. The included battery  – Microsoft doesn't provide exact details on how much juice you'll get – should provide up to an additional 70 percent of battery life. Microsoft says the keyboard will automatically disable itself when it's folded back, as to avoid any mistypes, and when it's closed it will automatically shut down the display to help boost battery life.

According to ZDNET, the Surface Power Cover will be available in the U.S., Japan and Canada at launch. If you want one, your best bet is to pre-order the Surface Power Cover right now. Otherwise you'll need to hunt down retailers on March 19 – Microsoft didn't reveal where else the accessory will be available at launch.