Male Adapter, 4" Black Flexible PVC Pipe The pressure relief valve protects

The pressure relief valve protects the compressor from excessive  backpressure if there is some sort of blockage in the airline or diffuser

but it is preferred by many for its amazing ability to trap small debris

filtration media and more

A large water change (approximately 90%) is required before each treatment

Male Adapter, 4" Black Flexible PVC Pipe The pressure relief valve protectsAll PVC Fittings are not the same! Unlike many available at department stores, our high quality fittings have deep sockets that allow for maximum bonding area, which is especially important when gluing Flexible PVC Pipe. This is a schedule 40 PVC Male Adapter used to adapt PVC pipe to female threaded fittings.