Product parameters: Blood oxygen saturation measurement range: 70%-99% Blood oxygen saturation measurement accuracy: ± 2% in the range of 70% to 99%, ≤ 70% indefinite Resolution of blood oxygen saturation: blood oxygen saturation ± 1%, Range of Pulse rate measurement: 30BPM-250BPM Pulse rate measurement accuracy: ±1 BPM or ±1% of measured value (whichever is greater) Index measurement range blood perfusion index: 0.2% to 30% PI blood perfusion index: ≥0.2%, ±0.1% Power consumption: less than 30 mA Auto power off: when no finger is inserted, it will automatically power off in 8 seconds Storage humidity: 15%-80% when working, 10%-80% storage</ p> Battery type: 2*1.5V (2 AAA alkaline batteries) Operating temperature: 5℃-4℃ Atmospheric pressure: 70Kpa-106kpa Material: ABS+PC Product size: 60*30*30mm Product net weight: 36g SpO2 monitoring parameter: < p>Oxyhemoglobin saturation (SpO2) Patient type: For all persons over 4 years old Measurement range: 70 - 99% Resolution: 1% Accuracy: between 70% and -99% ± 2% Oximeter saturation: an important indicator that reflects the state of oxygen in the body. It is generally believed that the normal value of blood oxygen saturation should not be less than 94%, and a value of less than 94% is considered insufficient oxygen supply. Heart rate Frequency pulse repetition rate (PR) BPM: Measurement range: 30 bpm - 250 bpm solution bpm: 1 Accuracy: 1% or 1 bpm Heart Rate: refers to the number of times the heart beats per minute, i.e. over a certain period of time the heart beats fast or slow. In the same person, the heart rate slows down during calm or sleep, and increases during exertion or agitation! Blood perfusion indicates the PI value: Range measurement range 0.2%-30% PI Resolution: 1% PI refers to the perfusion index (Perfusion Index, PI), and the PI value reflects the blood flow pulsatile, that is, the capacity for blood perfusion. The greater the pulsatile blood flow, the higher the pulsatile component and the higher the PI value. Therefore, both the measurement site (skin, nails, bone, etc.) and the patient's own blood perfusion (arterial blood flow) will affect the PI value. Since sympathetic nerves affect heart rate and blood pressure (affecting pulsatile arterial blood flow), the neuromodulator system or mental state of the body also indirectly affects PI values. Therefore, under different states of anesthesia, the PI value will also be different.