Battery Installation?We do not include batteries, you will need to purchase two AAA-batteries yourself. ?Load the two AAA batteries into the battery bin correctly according to the positive and negative signs. ?Push the battery lid horizontally in the low arrow direction. Note: Please note that the battery positive and negative properties direction must be installed correcily. Note?This pulse oximeter is for sports, home, travel and aviation use only, not for medical use. Causes of inaccurate measurement: Eating alkaline food may lead to inaccurate measurement of oxygen saturation, and finger temperature lower than the normal body temperature may also lead to inaccurate measurement. If your fingers are cold, please put hot water on your hands to make your fingers reach normal temperature before measuring SpO2 level. Portable Design?This pulse oximeter light-weight and compact, easy to handle and to carry with you for results at home or outdoors. Blood oxygen monitor is for sport and aviation use only, This device is ideal for use during sports activities such as mountain climbing, running, biking, etc. Accurate & Fast Reading?Accurately display the readings on rotating digital LED screen. Reading parameters of blood oxygen saturation is showed within 8 to 10 seconds on large digital LCD monitor display. Blood oxygen monitor has ergonomic design of natural latex finger cover to fit your finger skin more closely, all-round close-fitting measurement avoid inaccuracy. Pulse ox?Oximeter, uses a smart natural latex finger probe designed after most investigations, widely suitable for kids, teenagers, adults, elders, pregnant women, athletes, or anyone interested. Measure your blood oxygen saturation after flying, running, biking, skiing, high altitude climbing, and more. The portable oxygen monitors always measure at any time in travel and sports, better to reaching your fitness goals or prevent discomfort.