Powerful diagnostic tool for measuring alveolar Carbon Monoxide in PPM concentrations and percentage Carboxyhemoglobin * Operating from a single 9V PP3 battery for approximately 8000 tests * Measurements are obtained from a single expiration and are aided by an auto-zero function at turn on, combined with a breath hold countdown timer * Results are instantly displayed on the large, easy to read liquid crystal display * Features include, fast response time * 1 ppm resolution * Immediate display of CO levels in PPM & %COHb * Color light indicators * Capable of interfacing with COBRA, a windows based software package for performing and storing real time breath tests on your PC * 2 year warranty