In addition, the compression gauge is equipped with a pressure relief valve to reduce the risk of fuel injection by releasing pressure before disconnecting, ensuring safety during operation. 💙 【Wide Compatibility】 46-piece engine compression tester kit is suitable for most car, truck, bus, agricultural and marine engines, designed for modern gasoline and diesel engines, including HDi, TDCi, Pumpe Duse (PD) and old diesel and gasoline engines.