Piston check valves ensure media travels through a system in the intended direction and prevent backflow. Pressure on the inlet side raises the piston and opens the valve. When pressure on the inlet side of the valve is lower than the outlet, the piston drops into the valve seat to stop flow and prevent contaminants from entering the system. These valves are suitable for low-flow applications and low-viscosity media in various industrial, manufacturing, and treatment operations. Inline piston check valves direct system media straight through the housing without changing flow direction. Y piston check valves have an angled disc and seat to reduce flow resistance and minimize pressure drops within the system.