Keep ours in the glove compartment, gives my wife something to do as it's her job to hold the 'magic box' as we approach the barrier. The toll charges are debited automatically and the statement arrives the following month. Must admit that every year there is a moment of apprehension as we approach the barrier for the first time in case it no longer works but never had any problems.
The look on the faces of fellow Brits as they queue and we go on the left hand side unhindered is priceless.
