This review is for the Jamdok 3 inch folding mattress. It measures 75"L x 30"W x 3"Thick when lying open. It has an inch of memory foam on the top layer and 2 inches of a sturdier foam beneath that. It has a mesh cover that zips on and the underside is kind of a non-slip material. I wondered if the 3 inch one would be thick enough. For my purposes, using it on top of a sofa, it was exactly the right thickness.I purchased the mattress topper to use on a reclining sofa that I have been sleeping on for over a year. The sofa doesn’t recline back far enough and I am a side sleep, so I was sleeping lengthwise across the sofa which wasn’t very comfortable and resulted in back and hip pain, not to mention restless sleep. I’ve been sleeping on the sofa to be next to my husband who sleeps on a hospital bed and can no longer climb the stairs to our bedroom upstairs. I wanted a pad that was thick enough, but not too cumbersome to put on the sofa each night. This is perfect. It isn’t very heavy and it folds up in about 3 seconds. I put a jersey twin fitted sheet over it to cover the mesh. It tucks around it just fine.The mattress is very comfortable. The inch of memory foam is the perfect level of soft yet firm, and the sturdy foam underneath it smooths out the feeling of the recliner sofa under it which was not meant to be used as a bed. This actually feels like I’m sleeping on a normal bed and I can sleep soundly without waking up because something hurts. The mattress looks to be very well made and the quality is apparent. I am completely happy with this purchase.