It's been a while since the time when I got the breathalyzer ACE III Premium and now that I can write this because I did not want so the only reason to get drunk in order to test the device can; and the first results were me already a little too uncertain to make statements can - the values appeared to me rather too low. But comparative measurements with other equipment showed that the ACE III astonishingly accurate measures. The reproducibility is excellent, because it moved only in the 3rd decimal place; the reproducibility of the fluctuations when the same measurement is repeatedly (here very often behind the other as quickly as possible) performed. I would add - even if that is more likely to be higher, that you should leave at least 15 minutes alcohol and he first measurement between the last sip to measure not adsorbed in the mouth and throat area with alcohol. The device is small and portable; with a size of 10 x 5 cm only slightly larger than a credit card with a thickness of 1.7 cm at the thickest point can it just go easy to carry anywhere; This is also facilitated by a cloth bag in which the expensive equipment is well protected in case-to-wear. For storing at home the unit with accessories is well packed in a black padded plastic cassette which also has a very high quality. In it are located next to the device itself, the cloth bag called nor the manual, a second guide in the but only in English - describes how you can replace the sensor, then a list that facilitates the sending, a small product catalog with other alcohol testers , and especially with 5 other mouthpieces for 5 additional users, everyone should use his own. The first tip is already on and be pushed out to the device. It is not described in the manual, as another must be made: first I tried it with replacing, but quickly realized that it must be inserted in the first. Otherwise, the operation is simple; However, one must bear in mind that you have to blow into it until a clack sounds. In the manual it is pointed out that the device should be calibrated once a year; For this, the device must be, which is facilitated by the above Einlieferschein. On the stand also prices for calibrating, however different for different device types, and you really have to know that there is this machine to a trades electrochemical sensor, then you get to the right price, or 40 Euro. The two AAA batteries are in the supply built into the unit so that it is equal to the system without that something must pull out a sheet or.