Accurate blood pressure readings with state of the art aeroid sphygmomanometer Chrome-plated, precision crafted, easy to read 300 mmHg with air release valve Ideal for the cost-conscious healthcare provider looking for quality and affordability Latex free Key and instruction book are contained within a small plastic bag inside the canvas bag Note: When the manometer needle is within the rectangle on dial the product is calibrated. Should you need to calibrate it, please check the link Sphygmomanometers Calibration Instructions for the instructions.