|Simple, small, light-weight (50 gr. with batteries), easy to carry. Low battery signal. Automatic turning-off after 8 seconds without signal. Putting the finger in the sensor, the pulse oximeter will give you the oxygen saturation and the pulse rate in few seconds. 2 AAA batteries guarantee 30hrs measurements. A string to carry the device is provided. Included: instruction manual, batteries. Rubber protective cover (LDR196).