I had one for my first Newf and he loved it! That was the good news. The bad news is that he was just too heavy for it (150 lbs) and it popped! Actually it was a leak in the seams....
Good news, I took it back to the pet store I bought it from and got my money back. Bad news: the carpet, carpet pad and our upholstered bed! They had to be replaced! (They hold a couple of gallons of water!!)
I'm using the cool pads now from In the Company of Dogs catalog (on line at
www.inthecompa nyofdogs.com) and they are a gel that you soak in water and they stay cool for 4 - 5 days. They are not as big as the cool pads...but I just them on the Newfie beds and they seem to be fine.
We live in Southern Calif. so we are in our really hot part of the year...until October!