Billed as the ultimate commuter light Cat Eye AU-230 is a very neat hybrid of cutting edge and tried 'n' tested technology. At one end we have the clever automatic sensor shared with the brand's Reflex family that engages the five super-bright LEDs when it decides dusk, dawn or darkness have arrived. At the other and in stark contrast to the USB-or-nothing dogma, it's powered by four AA cells returning a very frugal 57 hours in flashing, 28 steady. Dynamo fan that I am, I have to say that these qualities lend themselves perfectly to those times when you've arrived at the caf' in daylight and emerged to find it very dark several coffees and one tall-tale too many later.

Taking its name from the Japanese for auto, the sensor works on a combination of light and motion so the light has to be moving and conditions dusk, or darker. Stay stationary for 50 seconds or so and it goes straight into hibernation, thus conserving battery life but thankfully, the slightest movement brings it back on stream so you won't be in danger come railway crossing, traffic lights or major junctions. Most of us will be familiar with the Opticube lens concept; it varies from model to model depending on intended use but is where lenses, reflectors and LEDs are matched for maximum output while maintaining efficiency.

Choosing Auto and setting out before dusk, I was quietly impressed by the way the five little LEDs just burst into life, in stark contrast to my own indecision as to whether flashing or steady was optimum given the conditions. Being a townie; the beam, while bright, isn't for navigating with although a steady fourteen mph is manageable along suburban stretches. Strobing seems perfectly synced to avoid confusion through congested traffic, tempering the lemming tendencies of sleepy pedestrians as I snaked through lines of stationary vehicles and there's plenty going on peripherally, greatly reducing the likelihood of coming a cropper turning right/changing lanes etc.

Early on, the intelligent systems' cutout induced a cold sweat but this split second panic saw an involuntary rocking of the bike and the light restored. Use a mini blinky, or simply override manually if this sounds too unnerving to you-there's negligible effect upon run times. Cat-Eye reckons 30 and 60hrs respectively and we've cruised pretty damn close-28 and 57 from the OEM batteries.

Verdict

Clever and competitively priced alternative to bottle type dynamos for urban duties or less frequent night riding beyond the yellow glow