I have had my s35 for a couple of years , until yesterday it has been a lifesaver. I will be sending it in for service and keep using it to save lives.
My BACtrack started giving me some really wild reading indicating I should be dead. So I thought it must be time to calibrate, sent it in, easy. Came right back in a short time, works great, and many extras came with it. the extras alone were worth more than the price for calibration.