The single-use BACtrack® SingleShot™ – 0.08 %BAC breath alcohol tester is a fast and easy way to determine if your %BAC is over the limit. Simply squeeze the center of the SingleShot to activate the test, and blow through the tube. If your BAC tests below 0.08%, the crystals will remain yellow. Above 0.08%, the crystals will turn blue-green, indicating a positive result. It’s that easy. The SingleShot’s indicator chemistry is laboratory calibrated and 99% accurate. This single use breathalyzer is perfect for on-the-go testing -- carry it anywhere, in your pocket, purse, or glove compartment.