I happened to see these the day I couldn't find any new pillow protectors in my linen closets. I was going to order the four pack, but then compared price per unit in the 4, 6, and 8 packs, and went with the 8. These are very high quality covers of tightly woven cotton. Although the materials are not what I associate with allergen blocking covers, the product description suggests allergy protection. The thread count may be fine enough to provide some level of dust mite barrier, IMO, but I can't say for sure. In any case they are very nice, and I can recommend them, especially at just over $3 each in the 8 pack.