Yesterday, we reported the technical specifications of the Surface Pro 2, the tablet that Microsoft is expected to announce between late 2013 and early 2014. Today, the same source has published the characteristics of a new cover called “Power Cover” and as its name implies, it includes an extra battery that will further increase the battery life of the Surface Pro 2.

The upcoming Microsoft surface tablet will be based on the Intel Haswell chips, offering an excellent autonomy, with a renewed energy saving system. According to the rumors, the Surface Pro 2 would integrate a fourth generation Core i5 processor that ensures a battery life of up to 7 hours. The Power Cover will look similar to the current Type Cover, but can also be used to power the tablet. The cover will be sold as an accessory for the new device.

The presence of a secondary battery will obviously have consequences on the size and weight. The Type Cover has a thickness of 5.33 millimeters and a weight of 250 grams while the Power Cover will reportedly have a thickness of 9.75 millimeters and a weight of 520 grams. In addition to a spare battery, it may also have some additional expansion ports.

However, the Power Cover will be distributed after the launch of the Surface Pro 2 and the accessory would be backwards-compatible with the Surface Pro and work with the next Surface 2 with ARM chips, but not with the current Surface RT.

In essence, the cover will perform the same functions as the Nokia Sirius’s keyboard rumored late August. Although such add-ons are not so new and already on the market like the dock keyboard of ASUS Transformer Pad series, but the key element is here — As Microsoft and Nokia are making a transaction that will be closed by Q1 of 2014, they may also have been collaborating for a single device as the Nokia merges into Microsoft.