ACCURATE : The A320E fingertip pulse oximeter deviates less than 1% under lab conditions. RELIABLE : We will never use any cheap material to make oxygen monitor, so 24 months of manufacturer warranty. Easy to use : The large Dual-Color OLED screen is large and bright, you can read SpO2 and pulse rate clearly even in strong sunlight. Include 2X AAA BATTERIES that you can use the pulse oximeter right out of the box, a Carrying Case to protect the finger oximeter from damage and dirt, a LANYARD for convenience.