BLT is a recognized medical brand. As a professional medical device manufacturer, BLT is committed to provide high quality medical devices and health care products more than 28 years. 'OXI tracker' free APP is easy to use via bluetooth connectivity. It automatically sync and store data. You could track and review your blood oxygen saturation and pulse rate anytime anywhere. APP display shows: blood oxygen saturation (SpO2), Pulse Rate (PR), Plethysmograph, pulse bar, battery power indicator, Perfusion index (PI), Respiratory rate (RR) *Peripheral perfusion (PI) is related to the signal strength and quality of the pleth waveform, increases the validity of the SpO2 by locating the strongest pulse signal. *Normal respiratory rate (RR) and peripheral pulse oximetry values (SpO2), which are major parameters in clinical practice, and become altered quickly in respiratory and cardiac diseases. (Increased respiratory rate is often the only visible sign of a respiratory infection) Weight: about 21g (exclude batteries) Dimensions: 60mm(length) 37mm(width) 31mm (height) Power Requirements: Battery: AAAx2 SpO2 Measuring Range: 0~100% Resolution: 1% Accuracy: At 70%~100%, 2%; At 0~69%, unspecified PR Measuring Range: 25 bpm ~250 bpm Resolution: 1 bpm Accuracy: 1% or 1 bpm, whichever is greater