General description Compression tester designed for a wide variety of petrol engines featuring 10, 12, 14, and 18mm spark plug threads. Technical specifications Pressure range: 0 - 300 psi (0 - 21 bar) Includes 10mm and 12mm dual fit components Includes 18mm adaptor 300mm flexi-hose with 14mm adaptor Usage Easy to read dial for accurate pressure measurement Side valve for quick re-testing