Thanks Ben! That makes sense. I have no problem paying for quality, just so long as I know it actually IS quality. Besides, A1's prices are actually better than some of the other places I've seen. Is there any way to know for sure if these are OEM parts? I checked the FAQ but didn't see anything listed.

Also, is the model number listed anywhere else on the filter? The metal plaque on the side of the filter is so worn that I can't read any of the filled in information. All it says is Nautilus Diatomaceous Earth filter.