DS8P1 & DT8P1 Series Inline Check Valve, 3/8 NPT Ports, 5 PSI Cracking Pressure, Up To 8.00 GPM

With 3/8 NPT ports, this valve matches a 3/8 NPT threaded line connection. Function-wise it is an inline check valve, so it allows free flow of hydraulic fluid in one direction only and blocks flow in the reverse direction.

Marine and offshore is actually one of the listed application types for this valve, right alongside machine tools, die casting, turbine control, and press equipment. The steel body and Buna-N seals hold up in demanding environments, and the 3000 PSI max operating pressure gives you solid headroom for most marine hydraulic circuits. Just keep in mind it's rated for low shock service, so you'd want to avoid using it anywhere reverse flow could slam back through at high velocity.