Trimline Bag Filters (TBF) are designed to be used as a pre-filter for heavy particulate, or as a stand alone filtering system. The Trimline Bag Filter bags feature a convenient liftout handle for quick removal. The screw on lid nut is designed for easy access to the filter bag for cleaning and general maintenance. 2” PVC socket connections. 100% polyester fabric bag element. Pressure gauge and air relief valve standard with each unit. Special screw on lid nut for easy access to the filter bag element. Bags must be ordered separately. Trimline Bag Filter Housing (50 PSI) Includes Air Relief Valve & Pressure Gauge (Non-Oil Filled)