Kersel KY-039 Finger Heartbeat Detection Sensor Module for Arduino(Shipping from USA) Reviewhttp://tinyurl.com/q5ybrjl Kersel KY-039 Finger Heartbeat Detection Sensor Module for Arduino(Shipping from USA) Working Voltage : DC 5V;Pin Quantity : 3 BodySize : 24 x 22 x 8mm/0.95" x 0.87" x 0.3"(L*W*T);Use IR LED and optical transistor to detect pulsation in fingers.Package Content : 1 x Finger Heartbeat Sensor Module