My friend, there are multiple options in the link. You can choose the product you need according to the picture to purchase. If you order incorrectly, you will need to bear the after-sales problem yourself Specifications: GPS Speed Sender Mini Size, Universal Type Application: AlI kinds of Speedometer, Tachograph High Accuracy only 0. 2% deviation mechanical speed sensor will be 3~5% deviation Anti-GPS Stationary Drift technology. Support both Negative & Positive Pulse output with Max 50,000pules/km suitable compatible for different gauges with programmable speed ratio and lowest 0.5km/h speed to start. Output two speed signals which are reverse Shockproof and Circuit Protection design Pulse/Odometer Compensation when in Tunnel or under Bridge Default Speed Ratio: 5000ppk 5000 pulses per km High quality GPS Active Antenna which percompatible for ms well in windy or heavy rainy weather. Mini Size: 4. 5cmLx1.9cmW, 100cm extended cable DC12V/24V Power Supply 6- 36V DC Cable Definition: - RED: Power +, DC8~32V - BLACK: GROUND - GREEN: Speed Pulse Signal Output + - BIUE: Speed Pulse Signal Output- Please connect GREEN or BLUE cable one of the two to your current Speedometer/odometer/tachograph. How does it work? GPS Odometer Speed Sender provides a reliable calibration-free replacement compatible for mechanical speed senders. Using data received from the Global Positioning Satellite network, the GPS Speed Sender calculates three-dimensional ground speed and provides a pulsed output suitable compatible for existing mechanical speed senders. This high-technology solution eradicates the dependency on vehicle specific parameters thereby reducing installation time and eradicating the need compatible for periodic calibration.