I purchased these for my king size down pillows, fabric was nice quality. Washed them on cold dred on low heat before placing on pillows and they shrank down to the size of a queen pillow instead of a king. I would pass on these unless you really need to fluff up some feather pillows.
I am not usually one to order an unreviewed product, but in looking at the options, this product seemed like the best fit for my needs. I ordered the pillow covers for my queen size pillows, some of which are feather and some of which are down alternative. These fit perfectly on both, and the deep gusset keeps them well-formed despite their being smushed into the covers. I don't yet know how they wash, but I imagine they will hold up nicely.