Make sure you're under the limit wherever you are with the BACtrack Keychain Breathalyzer. Featuring an Advanced MicroCheck alcohol sensor, the BACtrack Keychain accurately determines your blood alcohol concentration from a breath sample. Simply power on, blow into the folding mouthpiece, and your results will be displayed in seconds. | BACtrack Ultra-Portable Keychain Breathalyzer (BT-KC10-GN) - Green