Razer is offering a free keyboard case with qualifying orders until July 15, 2012. Razer has both good and bad products on offer, so what's worth buying to qualify for the offer?

Razer Deathadder

The Razer Deathadder brings up to 3500 DPI via the configurable software, and as low as 450dpi, while the mouse features an ergonomic black design with elevated clickable buttons that provide just enough feedback. There's of course a scroll wheel in the middle, which illuminates in a blue color along with/or the Razer logo on the body of the mouse, and two buttons on the left-hand side can be programmed for different functions (by default, back and forward). The mouse is optical, so there's a laser on the bottom rather than a ball.

Available now for $59.99, works with PC and Mac.

Razer Black Widow/Ultimate

Despite its terrifying name, the keyboard certainly isn't difficult to use: mechanical with the additional ten keys on the right-hand side, this keyboard is sub-$100 and offers great performance. It uses cherry blue switches which provide a good balance between feedback and noise - reds are silent, while blacks produce more noise - though the advantage of mechanical keyboards if that keys don't have to be slammed to register. This means the keyboards last for the longer.

The Ultimate version is more expensive but brings illuminating keys, useful for those early morning gaming sessions. It also looks great with Razer's traditional black-and-blue design.

Available now for $79.99 for the standard version and $129.99 for the Ultimate version. Both are for PC and Mac.

Razer Naga

The MMOG gamer's mouse, the Naga features 12 buttons on the left-hand side for binding every skill, and will be more than enough for game's like Guild Wars 2 where there are just 8 skills. The side panels are also interchangeable for different hand styles. A cool piece of software called the Razer Synapse 2.0 syncs to the cloud to download the latest software.

It has a 5600 dpi and a laser sensor and a 1ms reponse time.

Works with PC and Mac. Available now for $79.99.

Razer Mamba

PC Editor's Choice reciever, the Razer Mamba is pitched by Razer as the gaming mouse. It can be used wired and wirelessly, with a 1ms response time for the latter, 6400dpi and a laser and optical sensor.

There's a two-in-one charging box that doubles as the mouse's wireless receiver. Software allows the color to be customized across 16 million colors.

Available now for PC and Mac for $129.99.