The O2 Quickstick is designed for Nitrox Divers. A simple twist of the side knob will turn on and calibrated the analyzer to ambient air. Place the O2 Quickstick to a slightly opened tank valve for an accurate and reliable reading. The intuitive process requires only one hand to operate. The replaceable thermally compensated sensor maintains accuracy levels exceeding dive industry standards. After use, the analyzer can conveniently be turned off to preserve battery life and stored away in your dive bag. The Anodized Marine Grade Aluminum body can withstand the accidental slams of dive tanks and weight belts in the rugged environment on a dive vessel. The O2 Quickstick comes with a 1 year limited manufacturer warranty and the provided sensor has a 2 year Pro-Rated warranty.