August 7, 2026

Frigidaire EPTWFU01 vs ULTRAWF: Which PureSource Generation Is Yours?

Quick answer: ULTRAWF (PureSource Ultra) serves Frigidaire french-door and side-by-side models from roughly 2011 to 2018, sits in the upper-right interior, and is also sold as Kenmore 9999. EPTWFU01 (PureSource Ultra II) replaced it on 2018+ models, including Gallery and Professional lines and many Electrolux units. The two cartridges are different shapes and do not interchange. Read the code on your old cartridge: it settles the question instantly.

The Frigidaire family map

Cartridge code	Marketing name	Fridge era	What we sell
ULTRAWF (Kenmore 9999)	PureSource Ultra	2011-2018 french-door and side-by-side	ULTRAWF Genuine OEM
EPTWFU01	PureSource Ultra II	2018+ incl. Gallery, Professional, Electrolux	EPTWFU01 Genuine OEM
WF3CB	PureSource 3	2009-2015 side-by-side	WF3CB Genuine OEM
FPPWFU01 (PWF-1)	PurePour	Recent Frigidaire Professional/Gallery	FPPWFU01 Genuine OEM

Older PureSource generations (WF2CB and earlier) are covered in our PureSource comparison.

Why the wrong one will not seat

ULTRAWF is a slim cassette that slides into a dedicated slot; EPTWFU01 is a shorter cartridge with a different lock geometry. A mismatched cartridge either refuses to click home or seats partially and drips inside the compartment once pressure hits. If you are pushing hard, you have the wrong filter, not a stubborn one, and our $1,000 wrong-fit guarantee exists precisely for this family of mistakes.

The certification choice within your housing

Fit is dictated by the fridge; certification level is your choice. Every ULTRAWF and EPTWFU01 we sell is the Genuine Frigidaire cartridge, with the manufacturer’s certifications listed on its product page. If your city report flags lead or PFAS, the Genuine OEM EPTWFU01 (PureSource Pro) carries NSF/ANSI 42, 53 and 401, the strongest stack in our catalog. Check your city first with the free EPA water report.

Frequently asked questions

My Frigidaire is from 2018 exactly. Which one do I have?

Transition years shipped both. Do not guess from the year: pull the old cartridge and read the code, or photograph it for the free photo matcher.

Is the Kenmore 9999 really the ULTRAWF?

Yes, identical cartridge under the Sears label, from Kenmore 253-prefix (Frigidaire-built) refrigerators. Full mapping in the Kenmore number decoder.

Cheapest way to keep an ULTRAWF or EPTWFU01 fridge stocked?

The ULTRAWF 3-pack ($16.00 per filter) or EPTWFU01 3-pack ($18.33 per filter), both free shipping, or Auto-Delivery at 10% off forever. Full math in the cost-per-year guide.