Pentair OMNIFilter K4 Replacement O-Rings Kit for Under Sink Water Filter Housings, Pack of 4

For old 0B1 filter housing you need:OMNIFilter K4-DC6-S06 Omni M6 O-Ring, 3 PackI'm told the blue ring in that pack fits.

Would be nice to find just the one I needed, instead of 5 in a pack

I had to measure the gasket thickness with a Vernier caliper to find the right one to fit the OMNIFilter OT-32, but installation was quick and easy.Package contains 4 different-sized gaskets and 1 small tube of medical-grade silicone lube.You will need TWO (2) packages for the Dual-Cartridge OMNIFilter OT-32. I knocked off 1 star because I had to buy 8 gaskets to get the 2 that were needed.

I bought these for my well water cleaner.

Same as others have said, multiple sizes is wasteful and misleading. Wanted several rings to stock up, and ended having only two that will fit. Will find another supplier.

Bought the rings 2 years ago. On last filter change I had to reuse the ones I was using for 12 years, because the 4 different ones I bought at the time were too thin and would not seal. So I bought these and the biggest one still looks a micron too narrow but it is not leaking, however the second ring in the package is a completely different thickness and is unusable. Arrgh.

The picture shows 2 blue and 2 black "O" Rings. But the factory package contains 1 blue 2 black of the same size and 1 black larger "O" Ring. And of course I needed 2 blue "O" Rings for my Omni Filter. I called and the vendor made good on it and shipped another kit, but the 2nd pacakge contained exactly the same thing, so I have to assume the factory has changed what it includes in the kit. 4 stars is a balance between the package being incorrect, but excellent CS from the vendor.

I haven't actually used these yet, as I ordered them to have on hand for later when I need replacements. I cannot get these locally. I can say that they came reasonably fast, well packed and look good. If there is any problem with them when I use any of them, I will come back for an update. BTW, the o-rings are all about the same size. In the picture, they look different, but in person, not much. There are blue ones and black ones, and my understanding is that they are slightly different. Time will tell, and I will note better in an update.

Product quality is fine. The description clearly indicates that it is a kit and is suitable for a number of different filters. What is not clear is that you receive two different O ring sizes when only one will fit the BF7 model filter. Was hoping that the kit was two filters for my needs . Obviously one O ring not usable for my project.

Of the 5 rings in the package, only 1 fits the OK25 filter and the size measurement listed in the description.

They do not fit. The circumference is off.