FOR PETROL ENGINES: This automotive compression tester kit is suitable for petrol engines (cars, motorcycles, scooters and lawn mowers). CONTENTS: The kit contains corrosion resistant brass spark plug adaptors and 4 thread adapters: M18 x 1.5mm, M14 x 1.25mm, M12 x 1.25mm and M10 x 1mm. METRIC AND IMPERIAL: This tyre pressure gauge provides both metric (kg/cm²) and imperial (psi) pressure gauge readings.