Profile: Everfilt Inc. is a manufacturer of water and wastewater filtration and treatment systems. We distribute a full line of media and multi-media filters for the removal of suspended solids, turbidity, and many dissolved substances. Our RST-series flow restrictor combines the benefits of a restrictor valve, air vent port and sight glass, into one compact assembly. This unit also provides protection against accidental adjustment which can cause damage or media loss. The unit comes with 4" grooved ends for quick installation and easy inspection. The hex nut adjustment helps to protect against unauthorized adjustment. The RST provides durability and does not need painting.