The twin size barely fits the top of the mattress. We use it for out single sized cot and it's good for that..
The QS sheet, before washing, was a real struggle to get on my 8" mattress. Get the next size up!
Got these as they were an economical selection for our new king sized memory foam mattress that regular sheets pulled off of. Had to call to get the pocket depth which i got several different answers on. I would say they fit my new 13" mattress but only the corners do because they stretch, all of the sides don't come close. I would say more for a 10" mattress. The material is soft and washed well (I washed before using) but is very thin. Overall I would say in this case it's ok quality for the money. I was told it would fit a 15" mattress and it doesn't really fit my 13" mattress properly. They do stretch though when laying on them, allowing my memory foam on my mattress and my topper to actually work as intended. Shipping was super fast.