YH Maialan Replacement Filter For Shop Vac Filters 90304 90585 Wet Dry Shop Vac Filter - Perfect for Wet Dry vacuum cleaner Shop vac Filters 5 Gallon and above - Long

A filter swap shouldn’t require a parts hunt. I installed this YH Maialan 90304 filter kit on an older 12-gallon Shop-Vac that takes the common 90304 cartridge, and after a few weeks of woodshop cleanup, drywall sanding, and a couple of wet pickups in the garage, I have a good sense of where it shines—and where you might want to be cautious.

What’s in the box and how it’s built

The kit includes a pleated cartridge filter, a plastic end cap (the “lid”), and two foam sleeves. The cartridge measures about 7.25 inches in diameter, 6.5 inches tall, with an inner diameter right around 5.9 inches. That lines up with most Shop-Vac models that use the 90304 format. The pleats are uniform, the seam is tidy, and the plastic end cap feels adequately rigid without being brittle. The foam sleeves are medium-density and cut true; they’re not flimsy, and having two in the box is more useful than it sounds if you do any wet cleanup.

One design note: unlike some OEM filters that have a permanently closed end, this cartridge has an open end that’s closed by the included plastic cap. It twists into the filter and serves as the retainer. It’s a different approach, but after installing and removing it a handful of times, it didn’t strike me as a compromise in practice.

Compatibility and fit

On my Shop-Vac, the fit was snug at the canister collar and true at the height. The inner diameter slid on without fuss, and the outer diameter sealed well enough that I didn’t see dust bypass around the edges. If you’re unsure your vac uses a 90304-style filter, measure the inner collar on your unit; you want ~5.9 inches ID, and a height of about 6.5 inches. This kit is sized for 5-gallon and larger wet/dry vacs. If you’re running a compact or specialty unit, confirm the measurements first.

The foam sleeves are meant for wet pickup and are used on their own. They do not go over the cartridge filter. That’s important: the foam and the cartridge are alternate configurations, never combined.

Installation: quick and tool-free

Dry use (cartridge):
- Slide the cartridge over the central filter post or collar.
- Align and twist the plastic cap until it seats firmly.
- Give the cap a gentle tug; suction during operation helps keep it in place, but it should feel secure by hand.

Wet use (foam sleeve):
- Remove the cartridge.
- Slide a foam sleeve over the collar.
- Reinstall the plastic cap to retain the foam.

I prefer this to fiddly spring clips or oddball retainers. The cap threads engage easily, and the whole swap takes under a minute. If your vacuum requires frequent switching between wet and dry, the tool-free swap is a real convenience.

Dry performance and dust control

With the cartridge installed, suction on my vac felt as strong as, if not a touch better than, the tired OEM filter it replaced. More important, the filtration level was solid for typical shop debris—joint compound dust, MDF fines, table saw dust, and automotive grit. The manufacturer claims 99.97% dust capture. I’ll add a caveat: unless you’re running a sealed HEPA-certified system, you shouldn’t treat any standard shop-vac filter as a replacement for a true HEPA setup for silica or lead containment. That said, I didn’t see visible blow-by, and my air purifier in the shop didn’t spike during cleanup sessions the way it does with worn filters. For general carpentry and shop cleanup, it performed cleanly.

Fine sanding dust is where filters usually show their limits. After vacuuming up a couple of drywall patches and some orbital sander dust, the outer pleats loaded evenly without collapsing or oil-canning. A quick tap-out outside restored airflow, and a rinse brought it back to near-new performance. If you routinely tackle ultra-fine dust, pair the vac with a bag or a cyclone separator to extend filter life; that’s good practice regardless of brand.

Wet pickup with the foam sleeves

Wet pickup is straightforward: pop off the cartridge and switch to the foam. I used it to grab a few gallons of water from a leaky garden hose and some slushy shop floor mess with sawdust mixed in. The foam held shape, didn’t tear, and rinsed clean under a hose. The included plastic cap retains the foam just as it does the cartridge, so there’s nothing extra to buy.

A practical tip: let the foam dry fully before bagging it away or switching back to a bagged setup. Trapped moisture can get musty. Because the kit ships with two foam sleeves, you can rotate them—wash one, use the other.

Cleaning and maintenance

The cartridge is washable and reusable. My routine:
- Knock it out gently on a trash bin to dislodge the heaviest dust.
- Rinse from the clean side out with low-pressure water. Avoid pressure washers; they can damage the pleats and media.
- Let it air-dry fully, ideally overnight. Do not reinstall while damp—airflow will suffer and you risk moldy odors.

Replacement cadence depends on your workload, but a 3–6 month interval is reasonable for regular use. If you run a separator, you can stretch it much longer. Having the second foam and the washer-friendly cartridge means you’re not buying consumables every other month.

Durability and build quality

Over several cleanings, the pleats didn’t fray, the end glue line stayed intact, and the plastic cap’s threads showed no rounding. The foam sleeves haven’t pilled or torn. The cap’s “twist-in” design initially felt less reassuring than a molded closed end, but in use it never backed off, even when I tugged the vac around by the hose. If you routinely drag the vac over rough concrete, it’s still good practice to check the cap seating during setup. I would not glue the cap permanently; you’ll want to remove it to switch to the foam for wet jobs.

Airflow and noise

Fresh filters always perk up a shop vac, and this one was no exception. I noticed a modest drop in perceived pitch (a sign of reduced strain) compared to my clogged filter. More importantly, the vac maintained suction longer between tap-outs. With fine dust, it will load more quickly than a bagged setup, so consider a disposable bag for renovation work and keep the cartridge as the last line of defense.

What could be better

• End-cap confidence: While it stayed put for me, the twist-in cap design doesn’t feel as bombproof as a fully molded closed end. A slightly tighter detent or a gasketed interface would inspire more confidence.
• Not a HEPA system: The filter media performs well, but if you’re tackling hazardous dust, you need a true HEPA vac with sealed filtration. This is standard advice, yet worth repeating.
• Measurement matters: There’s enough variation among older shop vacs that you should confirm the inner collar and height before you buy. If your unit is an oddball, expect to shim or pass.

Value and who it’s for

Price-wise, this kit undercuts many OEM offerings and includes two foam sleeves, which saves a separate purchase if you ever vacuum liquids. If you maintain a single shop vac for mixed duties—garage, jobsite, and occasional wet cleanup—this is an economical way to restore performance without juggling multiple part numbers.

If you have a fleet of vacs or a HEPA workflow, you already know this isn’t a certified replacement for those environments. As a general-purpose shop filter kit, though, it hits the right balance of filtration, airflow, and cost.

Practical tips for best results

• Don’t stack the foam over the cartridge. Use one or the other.
• If you switch modes often, keep a spare dry cartridge on hand so you’re never waiting for one to fully dry.
• For fine dust (drywall, cement), add a bag or a cyclone. Your filters will last much longer.
• Mark the install date on the end cap with a Sharpie to track service intervals.

Recommendation

I recommend this YH Maialan 90304 filter kit for owners of 5-gallon and larger Shop-Vac–style wet/dry vacuums that use the 90304 cartridge. It installs quickly, filters fine shop dust responsibly for non-HEPA tasks, handles wet pickup with the included foam sleeves, and cleans up well for reuse. The twist-in end cap feels a bit less reassuring than a molded closed end, but it held securely in my testing and keeps the kit flexible for wet/dry swaps. For the price, the combination of performance, reusability, and included accessories makes it an easy upgrade over a clogged or aging filter. Just confirm your measurements and use the right configuration for wet versus dry, and it should serve you reliably.