Optical Heart-Rate monitor and pulse oximetry sensor moudle. From emitting two wavelengths of light from two LEDs (a red and an infrared one), then measuring the absorbance of pulsing blood through a photodetector. The signal is processed by a low-noise analog signal processing unit and communicated to the target MCU through the I2C interface. A programmable INT pin is also available. Uses 3-5V power supply. Size: approx. 14 x 14mm Color: Purple Package Includes: 1 Piece Heart Rate Click Sensor Moudle Note: Color maybe slightly different due to different monitor. The above size is measured by hand, please allow slightly difference. Thanks About Shipping: All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances.Any questions, please feel free to contact us During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours, wish you a happy shopping Thanks for your cooperation and we'll make you feel satisfied.