AlcoMate Prestige is a breathlyzer that DOES NOT require recalibration. Operates with semiconductor-oxide sensor, one-way-flow mouthpieces, cumulative counter, deep-lung air sampling and more. Great for Consumers and Professionals. FDA 510(k) NF/CE Mark Meets DOT/NHTSA requirements Accuracy: +/- 0.01% at 0.10% BAC Hand strap, heavy duty hard case, batteries included Deep-lung air sampling system Pressure sensor system One-way air mouthpiece Auto Power-Off Low Battery Indicator Cumulative Test Counter 1 year warranty No Recalibration Required