The Veridian SmartHeart model 11-50K is a Portable Pulse Oximeter. It safely monitors oxygen levels and pulse rate, and has a large LCD with red digital display. It accurately measures oxygen saturation of arterial hemoglobin and pulse rate, and accommodates a wide range of finger sizes: circumference approximately 20-75mm, user weight approximately 33lbs - 242 lbs. The LED display shows Blood-Oxygen Saturation, pulse rate and pulse bar. No prescription required. Has a low battery indicator, automatic shut-off and is latex-free. The complete monitoring system includes: Pulse Oximeter, lanyard, 2 AAA batteries and instructions.