Pulse Sensor is a well-designed plug-and-play heart-rate sensor for .It can be used by students, artists, athletes, makers, and game & mobile developers who want to easily incorporate heartrate data into their projects.The sensor clips onto a fingertip or earlobe and plugs right into with some .It also includes an open-source monitoring app that graphs your pulse in real time.Colour:black&redmaterial:ABS plastic: 3-5VFit for: Diameter: 16mmMagnification: 330LED Wavelength: 609nmDimensions:L 220mm x Diameter 16 mmPackage Contents:3 x Pulse Heart Rate Sensor ModuleOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.