Techni-ice HDR 4 Ply - White Sheets No Printing ,(5 Sheets) Better Than Ice or Gel Packs! Reusable, Dry Ice Replacement (11X15 INCHES)

I had some other ice packs for our cooler. They worked OK but I did not feel like they stayed cold for very long. The first time I used these, they sat in my cloth cooler, in my car, for ten hours. I took my food out when we got to our wknd destination. I left the ice packs in the cooler after I emptied it. 2 days later, when I went to pack up to go home, I found them to STILL be quite cold. They kept my things cold enough to get home. I was amazed. I'd buy more in a heartbeat! Only criticism that I have of them is that they take up a little more room than my old ones but I'll take their efficiency over the capacity.