ibgary,

Down is excellent but for me, it is kind of bulkier than what I need. I use an old helmet liner, from my younger days, back when part of my job was fighting wild fires, in the western states. The liner went inside my wildland fire helmet. Its made of thin, quilted wool and also has a chin strap. You can find the same liner at welding and/or construction equipment supply stores. They are about 10 bucks. The chin strap is superb at keeping the hat in place during the night.

I can use the liner by itself down to about 20 degrees. Below that I use a thin " Buff Type " head wrap under the liner hat. Only been down to 12 degrees with this set up but I was plenty warm.

Have a good 4th

I am not a computer guy but I will try to past a link below

https://www.ebay.com/c/3027324819