Custom Molded Products 25390 Filter Cartridge
Custom Molded Products OEM number • 75 sq ft • 5″ OD × 20.125″ long
25390 is Custom Molded Products's number for this cartridge, not a part you have to buy from Custom Molded Products. The filter itself is a 75 square foot cartridge measuring 5 inches across and 20.125 inches long, and Pleatco, Unicel, and Filbur all build it. If you read 25390 off an old cartridge or found it in your manual, any of the numbers below drops into the same housing.
Fitment notes
2-1/8 inch open top and bottom. Fits Pentair Rainbow Dynamic 75, RTL-75, and Dynamic Series V DSC-75 filters, plus Custom Molded Products 75 sq ft top-mount skim housings. Rainbow 17-2632 is the same cartridge ordered with Microban media (Pleatco PRB75-M).
What to buy instead
Replacements for the Custom Molded Products 25390
Each button searches Amazon for one of the numbers this cartridge is sold under. The OEM version is usually the most expensive of the set and the aftermarket versions are the same physical filter, so it is worth checking all of them before you order.
Every number for this filter
| Brand | Part Number | Type |
|---|---|---|
| Custom Molded Products | 25390 | The number you searched |
| Pleatco | PRB75 | Aftermarket equivalent |
| Unicel | C-4975 | Aftermarket equivalent |
| Filbur | FC-2395 | Aftermarket equivalent |
| Pentair | 17-2623 | Other OEM number |
| Pentair | 17-2632 | Other OEM number |
| Pentair | R173435 | Other OEM number |
Full specs, the cartridge diagram, and the complete compatibility list live on the PRB75 cartridge page. You can also see every 5″ × 20.125″ cartridge if you are checking a measurement rather than a part number.
Frequently Asked Questions
What filter replaces the Custom Molded Products 25390?
The PRB75 replaces it directly, and so does every cross-reference for it: C-4975, FC-2395. All of them are the same 75 sq ft cartridge at 5" outer diameter and 20.125" long. Buy whichever is cheapest at the time with solid recent reviews. The same cartridge also shows up as Pentair 17-2623, Pentair 17-2632, Pentair R173435, so those are not different filters either.
Is the Custom Molded Products 25390 the same as the PRB75?
Yes, physically the same filter. Custom Molded Products 25390 is an OEM number, meaning it is the code Custom Molded Products put on the cartridge that shipped with the equipment. Custom Molded Products does not manufacture cartridges. Pleatco, Unicel, and Filbur do, and they sell the identical part under their own numbers at a lower price. Match the dimensions against your old cartridge before ordering and you are covered.
Do I have to buy the Custom Molded Products version?
No. Nothing about the housing requires an OEM-branded cartridge, and the warranty on your equipment is not voided by using an aftermarket filter that meets the same spec. The reason to buy OEM is convenience, not performance. The reason not to is price, which is often a meaningful gap for an identical part. What matters is that outer diameter, length, and end-cap style all match.
What size is the Custom Molded Products 25390?
5 inches in outer diameter, 20.125 inches long, with 75 square feet of filter media. Both measurements need to land within about an eighth of an inch, and the end caps have to match so the cartridge seats correctly when you close the lid. Measure your old one rather than trusting a number that has worn off the label.
Last verified August 2026