During the 1950s, 60s and 70s, Porsche required each of their dealer service departments to have this tool for tuning carburetor and mechanical fuel injection engines.

Porsche realized that this was the only tool which would produce the accuracy required to calibrate air volume with adjustable throttle plates and have the sensitivity to calibrate air bypass screws for nonadjustable throttle plates. If each cylinder doesn't have exactly the same air intake volume, the horsepower produced by each cylinder will vary, causing the loss of power and shortened engine life.

This is the only tool that is 100% accurate, and works with all types of Porsche, PMO, and side-draft/updraft carburetors.