Which of the following tools is NOT required at every inspection station?

A diagnostic computer is not a mandatory tool required at every inspection station in Hawaii. While many modern inspection stations may utilize diagnostic computers to assess vehicle systems and identify potential issues, it is not a standard requirement. Inspection stations primarily focus on key safety elements such as lights, brakes, tires, and overall vehicle condition, for which other tools can suffice.

In contrast, the other tools mentioned play vital roles in vehicle inspections and are often considered essential. A lift is necessary for inspecting the underside of vehicles for structural integrity and component condition. A window light transmittance meter is crucial for ensuring that window tint levels meet legal standards for visibility and safety. A tire pressure gauge is fundamental for checking that tires are properly inflated, which is vital for road safety. Thus, the diagnostic computer, while beneficial, is not a requisite tool for every inspection station.