The Smart Port Brushles RPM and dual temperature sensor plugs it into a Smart Port equipped X-Series reciever. Join the red and black wires to any 2 of the 3 wires going to your brushless motor.  This allows you to read the RPMs. This measurement gives you the freedom to fine tune your prop/motor/battery combinations without any guesswork. This item includes 2 temperature sensors to ensure that the new prop does not fry your speed control or battery.  This item is compatible with FrSky Smart Port enabled receivers such as the X8R, X6R, X4R, etc. coupled with a Taranis transmitter.  Early Taranis transmitter users may require a firmware update to take full advantage of this sensor.

Specs

• Dimension: 29mm x 20mm x 2mm

• Weight: 6.7g

• Operational Voltage: 4 - 10 volts

• Current Draw:  25mA @5V

• Voltage Range of Motor Wires: 2 to 12S Lipo

• RPM Range: 1,000 to 300,000 RPM (for 2 pole motor)

• Temperature Range: -20 to 250° Celsius (-4 to 482° Fahrenheit)

• Smart Port ID: 5 (Can be changed with servo Channel changer)