Product Description: Checks cylinder compression from 0 PSI to 300 PSI. (0 to 21kg/cm2) Fits 14mm and 18mm spark plug threads Equipped with air-hold valve and gauge reset button 11-inch flexible hose 2-3/4" Gauge Package Include: 1x Pressure Gauge Check Features: 1. Made of high quality alloy steel, plastics and rubber materials, durable and practical 2. Includes 14mm and 18mm spark plug adapters 3. Adapters for a wide number of vehicles, spark plug types/depths 4. Compression gauge test set for engine cylinders diagnostic tester 5. Light weight, easy to operate 6.Suitable for lawn mowers. motorbikes, cars, and trucks with petrol engines .