SPECS:
Insulated with polyester microfibers. This version is 26" x 77.5" x 2.8" thick; weighs 39 oz.; R-Value 4.9 (will keep you warm to about zero degrees F with a proper sleeping bag); packs into a stuff sack 6" x 12". It is made in smaller, lighter versions, but for kayak camping there is no reason to get anything smaller. Splurge on the largest one and enjoy the luxury.
The Exped Synmats and Downmats are widely recognized by experienced backpackers as the most comfortable mattresses on the market. After getting the Synmat 7, I got rid of my Big Agnes Insulated Air Core (for backpacking) and my Thermarest Luxury Camp mattress (for car camping)---the Exped does it all; no need for more than one mattress.
The Exped is the most comfortable camping mattress I've ever slept on. It's so thick you don't feel the ground at all. It's wide enough to keep your arms from falling off the sides. The material and construction appear very durable. It doesn't lose air. This mattress has a pump built into the mattress. You can inflate it either with your hands or with a foot. It takes about 50 pumps---a couple of minutes. Not exactly fun, but it works well and is worth the effort for a great night of sleep.
For summer camping you turn the mattress over and sleep on the uninsulated side.
This mattress easily deserves a 10!