Here we did half of one window with unfiltered water and the other half with Stain-Less filtered water. The unfiltered on the left is horrible. The right is much better but, while it’s hard to see in the photo, there are actually a few small spots on the Stain-Less Filter’s side. Water filtration and spot-less kits should be thought of as “less spots” systems, not “spot-less” products. They only lessen the spots, but the Stain-Less Water Filter really did amaze us. It worked extremely well and that’s not something we say too often. It cut down our wash time by at least half and the proof is very evident here. Check back on this one in a future issue of RV Magazine -- we’re gonna give the Stain-Less Water Filter a tough, long-term test.