4 Pack 211+ Replacement Washable Pre-Filters for Blueair Blue Pure 211+ air Purifier, Removes Pollen, Dust, Color Include 2 PACK Lunar Rock and 2 PACK Diva Blue Pre-filters

I was surprised at how cute they look on the 211+ auto. The original outside pre- filter is made of a hemp like material. I was worried the tighter knit might interfere with process but it seems to work nicely. Maybe it stops more particles from getting in than the loose knit filter? I will change it ad if I notice anything in the fall when I use it more.

These save so much money on air filters. Wash up nice, easy to put on. I have them on my air purifiers and bought them for my mother's. Saves so much money.

Easy to clean and change. You can add some color to the room or tone it down. Filtration is good and does not appear to impede air flow.

I like to change these out frequently - I machine wash delicate (no fabric softener) and let them air dry. Works perfectly. Would have given 5 stars except for the fact that the blue covers did not look great when stretched out on the units - the color looked 'uneven', and a tiny bit see-through. No issue with the grey. Could just be the lighting in the location in my home.

A little thinner than the originals that came with it but they work fine and no complaints on the price.Another bonuse is that you can change colors from time to time.I haven’t tried to wash one yet (I always just throw the originals in the laundry) but I don’t expect any problems.

fits my blue air and stops tons of unwanted junk from passing through the holes. filter still does its job, but this is essential. blocks so much from entering the filter zone and is machine washable. love it.

Made of same material as original filter colors are as pictured, bright. Easy to wash and are holding up nicely.

Seem to be approximately the same quality as the prefilters that came with my Shark vacuum. They do go on a little easier than the originals which is a plus. Haven't washed them so I have no information on shrinkage.