KNOW YOUR O2? Mr. Blue Bear Pediatric Fingertip Pulse Oximeter by Blue Jay Fingertip Pulse Oximeter for children uses a cartoon appearance design, reducing the fear of children Small size and lightweight design will not cause too much pressure on children's fingers OLED screen 4-direction display Pule bar Plethysmogram Parameters; SpO2 PR Low battery prompt Takes 2 AAA batteries (included) 49mm L x 28mm W x 28mm H Weight 35g ( 2 oz) Pediatric pulse oximeter can be used on the finger thickness between 9mm - 22mm Can be used on children who are two years or older