Keyring device clue to drinking and driving

Drivers who stop off for a quick one on the way home will be able to check their blood-alcohol reading on a keyring-sized breathalyser.

Five coloured light emitting diodes on the Korean-made device indicate how much you have had to drink.

Green indicates less than .01 per cent and yellow between .02 and .04 per cent.

Amber indicates .05 to .09 per cent, red .10 to .35 per cent and dark red higher than .36 per cent.