sensitivity sensor enables quick and accurate BAC results to support responsible driving decisions. Innovative storage design keeps the mouthpiece inside the battery compartment for cleanliness and security; builtin mini flashlight enhances usability in low light conditions. Compact and lightweight at 60 grams; fits easily in a pocket or purse; suitable as an essential companion for events such as weddings and parties where checking alcohol levels is helpful. User friendly operation: insert three AAA batteries (not included); attach the nozzle; press the start button. After a brief countdown, blow into the device for a few seconds to obtain your blood alcohol concentration reading. Use scenarios: After a dinner, party, or bar visit to determine whether it is safe to drive or if a ride should be chosen. At weddings, parties, or social events to monitor or guest alcohol levels. When returning home or traveling after social events to verify BAC before leaving the venue or selecting transportation.