Excellent Product. I bought the S80 to check my B.A.C. before driving. I bought another S80 just to verify that the first one was still accurate. Both are very accurate and I've check them against a court mandated unit. Recently Bought a C8 which works excellent also, with a count down to when you will be sober, it also interacts with an App on my cell phone. Recently had both S80 units recalibrated and they working great. Also plan on giving one to my sons so they can be safe while driving.