I bought these to help prevent tangles while I slept, and I believe they do help to keep my hair from getting messed up while I toss and turn. The only downside is that the metal zipper pulls are annoying. They rattle when I move, especially if they are touching my wooden headboard. I solved the problem by cutting off the metal zipper pull tabs with tin snips (wire or bolt cutters would also work). Eventually, I might thread some narrow ribbon or cording thru the slider and knot the ends to use as a zipper pull, but I haven't gotten around to it yet. In any event, I can still open and close the zipper just fine by grasping the slider, Overall, I love these pillow cases, and the price is right!