This compression tester is quickly set up on your car to give you accurate readings for finding faults in valves, piston rings, cylinder bores or head gaskets. Suitable for petrol engines. The quick release pull down coupler is easy and fast which allows you to switch between the flexi and the rigid tube. Specifications: Gauge with SAE and Metric readings. 0-300PSI. Side release valve. Flexible hose. Cone adapter to fit all spark plug holes. Kit Contains: Flexible hose. Cone adapter. Easy to read gauge. 14mm and 18mm Screw Adaptors.