How to get accurate ketone readings? 1. In order to get accurate ketone readings, please exhaust the residuals completely with the ketone meter before your first use by running the keto breath tester 3 times without blowing,because each ketone breath analyzer was tested during the production before shipping to warehouse, there maybe residuals; if you want to test another person consequently after your testing, please also kindly exhaust your previous residuals. 2. Please blow immediately within first 5 seconds when displaying BLOW on the ketosis tester if you finish the residuals exhaustion step, because the ketone breath tester starts analyzing the breath right after the first 5 seconds. How To Test Your Ketone? 1.Hold the power button for 3 seconds until the device turns on 2.Wait 20 seconds countdown for device warming-up, exhausting the residuals 3.Blow with the mouthpiece for 5-6 seconds, the testing result will be analyzed and displayed on the screen Kind Reminder: Readings will be slightly different from the blood meter because of different analyzing methods. Please catch the same keto meter to track your own personal ketosis records, only in this way you can get your own changing status. Package Contains: 1x portable ketone meter 10x replaceable mouthpieces 1x carrying string 1x user manual 2*AA Batteries are not included