This EH series is interchangeable with MHA RV SERIES, PARKER 339 SERIES, and GROMELLE 654-Z SERIES. Stainless Steel Product. One-way stainless steel 316 check valve for in-line use. Suitable for any type of hydraulic applications. This series check valve allows flow in one direction and blocks it in the opposite direction. The flow is only allowed once a pre-set cracking pressure is reached. Customized cracking pressure is available. This series is widely used in corrosive environments: marine, oil and gas, chemical, pharmaceutical, and nuclear.