Used twice - includes serial cable and software. Race Technology's AP22 performance meter is a box with a display that can be used to accurately measure your acceleration times, braking distances, tire grip, quater mile times, horsepower,g-forces, and other performance indicators - but the best part is that because it uses accelerometers (and optionally GPS) it does not require any installation in the car whatsoever. It can be placed on the dashboard (or other relatively flat surface) and you can start testing immediately. You can even use it on bikes and ATV's! The performance meters run off 2 internal "AA" batteries, so they don't even need a connection to the car's 12v supply. Cutting edge features of the performance meter include: Digital accelerometers, Built in flash memory, Data download to a PC for detailed analysis, upgradeable with more memory and GPS, No Installation required - not even external power. Optional serial (RS232), analogue and CAN outputs. The AP22 measures acceleration times, braking distances, cornering forces, vehicle power etc etc. The results are displayed during and after the run on the LCD screen on the unit. The AP22 also allows you to store runs and results in internal memory and download them onto your computer at a later date. If you buy an AP22 meter, you can use powerful analysis software which is free to download from www.Race-Technology.com. $185 SHIPPED!!!!!!