Want to work out while you text and post Facebook updates? Here's a product just for you. Dubbed the ToneFone, it is the heaviest case you can buy to slap on your iPhone.

How heavy is it? ToneFone is available in 1 or 1.5 kilogram versions, and it is made up from 100 percent British steel. The cover is rubber-coated to prevent it from slipping out of your sweaty hands when you work out.

The heaviest version will set you back $42. [DesirableBody via The Gadgeteer]