... D), STC (HVT), and Hyperbar Top Stop Injectors. Top Stop Setting Fixture-All PT (type D), STC (HVT), and Hyperbar Top ... STC (HVT) and hypervar top stop injectors). This Top Stop Setting Fixture used to the test of the injector. After the ... the point where the plunger top stop, or plunger travel setting can be made. PTQC injector top stop ...