Oh my goodness... I was SO excited when I saw these!! I have a very large pup that sheds like an old Christmas tree! We have ALWAYS had slip covers on the sofa. I’ve never liked the way you have to constantly tuck the blanket like slip covers back. So when I saw these on Wayfair, I jumped on the purchase button! 
My excitement quickly wore off when I tried to put them on the cushion... the elastic is barely stretchy, which meant I had to pull and tug until it finally went on. Then we sat down, and POP went the corners. I had to pull and tug so hard to get it back on, the elastic broke. I imagine if you have very small couch cushions it may work. I hope they make a bigger size or have SUPER STRETCHY elastic!! I really wish it had worked for me...