GPS Speedometer;140 MPH;w/ RALLY-NAV Display;Plug and Play, no calibration required;Utilizes up to 3 satellites simultaneously and samples 10 times per second;12 and 16 volt compatible; California Residents: WARNING Tickets are no fun. Calibrating a speedometer is not a great deal of fun either. AutoMeters Electronic Programmable Speedometer makes short work of both, providing an easy to install and easy to calibrate solution that will help keep your speed exactly where it needs to be. Compatible with most factory and aftermarket speed senders, you will wonder why you ever struggled with a speedometer before. Calibration is as simple as a two mile drive, or for even easier operation, AutoMeters 5289 GPS Speedometer Sender is a simple plug and play solution for any application.