This handy Alcohol Tester attaches to your keyring. Simply blow into it to test your blood alcohol level. Invaluable for the silly season! Breathe into this keyring tester and brace yourself for the results: green light = under 0.02% BAC; yellow light = 0.02% - 0.05% BAC; yellow & red lights = over 0.05% BAC. Handily, the keychain also comes with an LED flashlight. ** Please note: this equipment is a novelty item and is not to be used to test Blood Alcohol Content in relation to driving or any other such measures of intoxication as set by the government or medical agencies. Please read instructions carefully before use. thumbsUp! takes no legal responsibility for the results of the breath test.