The CONTEC CMS50M finger tip pulse oximeter,is a lightweight, portable device used for measuring both heart rate and blood oxygen levels or SpO2.Read accurate results for Oxygen Saturation and Heart Rate on a LED display with an accuracy rate of ±2%. Screen Rotation and Screen Brightness Options Available. Continuous bar-graph display, the higher display indicates a stronger pulse. Pulse waveform shows the Pulse Rate. Screen automatically shuts off after 5 seconds of inactivity. Use two AAA batteries for 20 hours of use! Simply place your finger inside the antimicrobial vinyl sensor and have these vital measurements instantly displayed on a vibrant LED screen NOTE: this product is intended for sports and aviation use only and is not a medical device.We are the direct manufacturer, there is a clear screen protector which can be removed before use.