Razor Ripstik cashes in on the caster board wave.

Hot on the heels of the EssBoard, the eXboard and the Wave Board comes another two-wheeled caster board, the Ripstik from Razor. Feeling a bit like a snowboard to ride, caster boards look kind of like a skateboard with a twisty bit in the middle - but they use a single, free-rotating caster at each end rather than the skateboard's four wheels on two flexible axles. Fishtailing the rear end of the board produces forward power, meaning a rider can climb a hill without putting his foot down - and the unique steering properties of a rotating caster at each end mean the Ripstik turns on a dime under a pair of expert feet.

We're not sure who started the caster board craze, but companies across the world are starting to bring them out. The latest, Razor's RipStik, seems a good example of the genre. While they're perhaps a little less intuitive than a skateboard, our road tester found caster boards safer, as the intrinsic dynamics of the rotating casters don't have the skateboard's tendency to flick out from underneath you - and the board tilts to the ground when it stops, feeling quite secure.

The motion of the Ripstik is better demonstrated than explained - see the videos on the Ripstik website.

It seems to be a fun time in personal-powered transport, with exciting developments like the similar but unjoined Freeline Skates gathering momentum to push forward the evolution of the skateboard in interesting directions. With a hugely established company like Razor now getting in on the action, it seems the caster board is about to hit the big time.