Bought this unit Nov 25, 2016 and it seemed fine when no alcohol was present - 0.0% readings. First time I used it with alcohol present my reading was 1.41% and my wife's reading was 1.51%. I guess we are both dead... These readings were on the 11 and 12 uses according to the counter on the device.
Very happy with the experience I had with this website as well as their product. We have three of their devices and have never had an issue with any of them.
the unit was a replacement for another unit that failed in the past and never worked well. So I experienced two s78 failures, these machines need to be recalibrate to insure the safety for the user.