This is a Pentair 25021-0025 Modular Media Conversion Kit for Sta-Rite System:3 Modular Media SM Series D.E. Filters Models S8M150, S8M500; 25 Inch. Measures 11-3/4 inches in length by 7-1/4 inches in height and 9-1/2 inches in width.
This kit includes: Baffle and Bulkhead Fitting (25021-0101), O-Ring 35505-1428, O-Ring 35505-1429, Elbow and Bulkhead Assembly (25021-0100), O-Ring 35505-1425, Bulkhead Retaining Nut 24752-0050). Filter cartridge must be purchased separately depending on your model.