Frigidaire ULTRAWF vs WF3CB: Which Filter Fits?

Updated July 2026 · ClearTap editorial · Frigidaire refrigerators

Frigidaire hides the answer in plain sight, and almost nobody looks. The two filters that fit the overwhelming majority of its refrigerators aren't hard to tell apart once you know the trick — one is a flat oval, the other a plain round tube. But the box art photographs them from angles that make them look identical, and the PureSource names (2, 3, Ultra, Ultra II) sound like sequels rather than incompatible parts. So people order by name, receive the wrong shape, and wonder why it won't push in.

The shape test settles it in one look

Forget the names for a second and just look at the cartridge you're pulling out. The ULTRAWF has a distinctive flattened, oval cross-section — hold it end-on and it looks like a stadium, not a circle. It pushes straight into a matching slot, usually in the upper-right rear corner or along the ceiling of the fresh-food compartment on French-door units. The WF3CB is an ordinary round tube that pushes into a circular port, most often in the upper-right rear of a side-by-side. Oval socket, oval filter. Round socket, round filter. There is no adapter that bridges the two.

ULTRAWF and WF3CB, compared

On paper the two clean the same things — matching NSF 42 and 53 claims, matching 200-gallon capacity. The choice is purely mechanical. This is a fit decision dressed up as a product decision.

The PureSource naming ladder

Frigidaire's own naming is half the confusion, so here's the ladder laid flat:

• WF2CB (PureSource 2) → WF3CB (PureSource 3): the round-cylinder line. The WF3CB is the current version; a fridge that used the older WF2CB generally moved to the WF3CB.
• ULTRAWF (PureSource Ultra) → EPTWFU01 (PureSource Ultra II): the oval line. Newer French-door models spec the EPTWFU01, which shares the oval profile. Check your model before assuming an ULTRAWF fits a very recent unit — Frigidaire lists them separately.

The takeaway: "PureSource" is a family, not a filter. The digit or the "Ultra" tag is what actually maps to a shape and a socket.

PAULTRA is not a water filter

One more trap, because Frigidaire pulls the same stunt LG does. You'll see PAULTRA and PAULTRA2 in the search results next to ULTRAWF. Those are PureAir filters — round air fresheners that deodorize the compartment. They do nothing for your drinking water. If you meant to replace the water cartridge, ignore anything with "PA" in front; the water filters are the WF and ULTRAWF/EPTWFU01 codes.

How often to change either one

Both carry the same six-month, 200-gallon rating, and the gallons are the real limit. A busy household running the dispenser and ice maker daily can exhaust 200 gallons in under five months; a light user coasts past six. The symptoms are the same on both shapes: flow weakens to a dribble, chlorine or a stale taste returns, or the ice starts to look and smell off. Frigidaire's indicator light counts time, not water, so let taste and flow overrule the calendar.

Common mistakes

• Ordering by name instead of shape. "PureSource" spans both an oval and a round line. Look at the cross-section of your current filter first.
• Confusing ULTRAWF with EPTWFU01. They share the oval profile, but newer models spec the Ultra II. Verify by model before assuming they swap.
• Buying a PAULTRA thinking it filters water. That's the air freshener. The water cartridges are the WF and ULTRAWF codes.
• Forcing a round WF3CB into an oval slot. It won't seat, and pushing hard can crack the manifold. Wrong shape, full stop.
• Skipping the flush. Push in the new cartridge, then run a few gallons through to clear carbon fines before drinking or making ice.

FAQ

General information based on manufacturer specifications and NSF/ANSI standards, not independent lab testing or medical advice. Filter performance and pricing vary by model, water quality and region. For health or legal decisions about your water, test it through a state-certified laboratory.