The Sealey Cylinder Leakage Tester 2-Gauge is designed to detect a variety of common engine faults.Twin gauge manifold shows percentage of cylinder leakage and cylinder pressure.Suitable for use on any petrol engine with 10, 12 or 14mm spark plugs.Supplied in storage case with instructions.The Sealey Cylinder Leakage Tester 2-Gauge is designed to detect a variety of common engine faults including: worn piston rings, worn valves, cylinder head cracks and blown head gaskets. It is suitable for used on any petrol engine which has 10, 12 or 14mm spark plugs. It comes supplied in a storage case with instructions.Please note: For spark plugs fitted into a deep recess, VS200/A Long Reach Compression Tester Adaptor may be required.