PRECISE MEASUREMENTS: Digital compression gauge with incredible 0.5 display resolution within 1% of precise pressure from 10-250 PSI, for quick and accurate checking of gasoline engine compression. Acrylic glass gauge cover with scratch-resistant coating and Protective rubber cover with excellent shock absorption. A built-in one-way valve with pressure maintaining function ensures that the pressure gauge obtains the maximum pressure at the spark plug during the compression process. Package: Including 10 Connection Adapters --- 11 in 1 Engine Tester Kit, including 1 Spring Buckle Gauge; 5 Pieces Brass Adapters M10, M12, M14, M16, M18, Wide Use; 200mm Metal Extension Rod Connector One , two 50mm metal aluminum straight rods and curved rods, one extension rod hose with M12*1.25 thread. SMART DISPLAY & BLEED VALVE: Large, backlit LCD display shows large, clear 4-unit numbers. Automatically shuts off after 2.5 minutes of inactivity to preserve battery life. Side bleed valve allows repeated testing without disconnecting the hose Application: Gasoline Engine Cylinder --- Equipped with different sizes of swivel and push-in adapters, widely used for most types of gasoline gasoline engine cylinders and deep spark plugs, common in motorcycles, lawn mowers, cars, trucks, ATVs and many more. Not suitable for diesel engines.