I wonder if anyone has experience with these. I was looking for a Big Agnes Overbag to use with my bag at a store in Lexington KY that carries BA products. The manager suggested a
Sea to Summit Thermolite bag. Some are rated to add 40 degrees to your existing bag, of course provided you're using a mat, which I do.
Thier claims are this.
Fits inside of your primary bag.
Much lighter than an Over Bag/Sleeping Bag Combo.
Various bags rated 25 - 40 degrees additional protection in cold.
Extends the life of your current bag by keeping skin oils and persperation away from your bag.
Can be use seperately as a mild/warm weather bag.
Small, lightweight, and fits into a small stuff bag.
Costs around $69 - $70, depending on chosen model vs. up to 3 or 400 bucks for some Over Bags that are bulkier, and heavier, and larger than your primary bag.

Hoping to find someone here that has had experience with these.
Do they live up to their claims? Pretty lofty claims if you ask me, but I have no idea. $70 bucks is a great deal if they really do the trick.

Thanks ahead for your input.