Fingertip Pulse Oximeter C1F is designed for spot-checking blood oxygen saturation levels and pulse rate. Using it,athletes,pilots and people who would like to know their SpO2 and pulse rate can get accurate readings quickly. Operation of this oximeter is simple and convenient.You just need to plug one of your fingers into the comfortable clamp and press the button on the front pannel(Details please read the attached users manual). Its small size makes it easy to carry around in its durable carrying case.Simple operation allows it to turn on and off with the touch of a button. This is not a medical device,perfect for sports and aviation. Package contents:One Fingertip Pulse Oximeter C1F with lanyard,users manual,durable carrying pouch, two AAA 1.5V alkaline batteries could be continuously operated 30+ hours.