The Zacurate Pro Series 500DL fingertip pulse oximeter is manufactured according to the CE and FDA standards set for pulse oximeter designed for sports enthusiasts, pilots or anyone who wants to obtain their SpO2 (blood oxygen saturation levels) and PR (Pulse Rate) on the go. The LED display now faces the user so that the user can read it easily. We have upgraded internal hardware and software components of the pulse oximeter. For example: the pulse oximeter can now display SpO2 up to 100%! Taking a reading is easy, just clip it on to your finger and turn it on at the press of a button. The large LED display makes viewing the results a snap. Its small size makes it easy to carry around and a lanyard is also included for added convenience. Comes with 2 AAA batteries and a silicon cover to protect your pulse oximeter from dirt and damage. Zacurate is a registered trademark of USPTO. We will actively and aggressively pursue any parties who infringe on our intellectual property rights to the maximum extent allowed by the law. Beware of Imitation, Buy Original. Zacurate Pulse oximeter is designed in USA. This device is for Sports & Aviation use only and is not a medical device. Note: Low blood perfusion can affect accuracy of your readings. Warm your hands and fingers before taking your measurements by rubbing your hands together. Remember your pulse oximeter is measuring your SpO2 and PR based on your blood flow. If the blood flow in your finger drops below a certain level, the pulse oximeter will not be able to function. It usually takes 10 seconds to get a reading. Some people though may require a longer time for the pulse oximeter to optimize its sensitivity. You may have to wait about 30 seconds for the readings to stabilize. Keep your hand still while taking a reading - any movement can cause the device to reset its' reading. Nail polish and fake fingernails may cause false readings. If possible, switch to an unpolished nail or consider another application site.