Wireless finger heart rate monitor. •Cardiogram chart, average heart rate and blood oxygen measurement. •Measurement using infrared ray tunnel. •It works with two AAA batteries. •Includes 13cm long carrying lanyard. Interior coated with silicone.Battery: 2 AAA batteries (not included) Landyard length: 40 cm Working temperature: between 10º and 40ºC (50º and 104ºF) PVC Metal Alloy