Even if you have double vision you can understand the alcohol tester. If you're under the limit a green for go signal will show you are under, if the red light comes on you are over the legal limit, simple!
The pocket size alcohol tester gives a good indication as to whether you are over the UK limit to drive your car, will not help in the USA! The results are quick, showing on its LED display. Pen shaped with integrated clip for wearing and funky brushed aluminium finish.