This cylinder leak detector set quickly diagnoses internal engine problems such as bad rings, valves and leaking head gaskets. The dual gauges feature metal bezel with rugged rubber protective outer boot. Input gauge scales read 0-100 psi, second (measuring) gauge measures in % leakage. This leak-down gauge reads 0 to100% leakage in 5% increments. The easy-to-read gauges are designed for proper testing and accurate results. This leak detector set is suitable for use on any petrol engine with 12or 14mm spark plugs. It can be used for almost all cars, motorcycles and trucks. All tools come in a blow molded case for easy storage and transportation. Delivery includes pressure gauge, cylinder leakage gauge, 2 x spark plug adapter, quick connect/disconnect hose and regulator.