Forespar MF-841 Replacement Duck Bill / Cap Assembly
- This simple valve system when incorporated in the top of a vented loop allows air to enter the line when it is not in use
- Then it effectively seals as water or other fluid passes through
- Molded in Marelon®, vent will not corrode
- The duckbill one way valve is designed to seal properly if particulate matter is present in fluids
General Note: Forespar threaded plumbing fittings (like most true marine plumbing fittings) use NPSM Threads - National Standard Free-Fitting Straight Mechanical Pipe Thread. NPT - National Pipe Threads are tapered, NPSM Threads are parallel. The two types are not designed to work together.