OLED screen, acrylic panel, high-speed computing chips , anti-skip silicone inside, medical-grade silicone finger mold and various electronic components of oxygen finger monitor, all adopt high-quality materials and components. The deviates less than 1% under lab conditions. Plethysmograph and Perfusion Index can help you to judge whether your measured SpO2 and Pulse Rate is properly. Alarm function-Auditory alarm to warn you when your SpO2 and Pulse Rate are beyond set limits. The item automatically turns off 6-8 seconds.