Fingertip Pulse Oximeter with 4-Way Display, 6,000 Spot Checks, OLED display. Adjustable sleep monitoring up to 8 hours. Determine oxygen level in blood (SpO2) in 8 seconds. Measurement range is 70% - 99%, ±2% accuracy, ±1% resolution. Alarm beeps to indicate oxygen level and heart rate. Simultaneous display for test value and bar graph. Low battery indicator, 8 seconds automatic power-off. Very light: weight only 2.2 oz with batteries (not included). Comes with lanyard for easy carry.