This is a prototype for Cerevellum's bicycle rearview monitor that will give cyclists a look-see what's behind them.

The unit features a 3.5-inch screen and 4-hour battery life, along with 32MB of storage for workout data and four USB ports for expansion modules.

Such modules are to include GPS and heart-rate monitors, due to ship soon after the unit goes on sale for around the $200 mark.

We are all for teching up every possible aspect of your life, but would question the wisdown of a gadget that encourages you to look down, rather than forward, on a bike...