Genuine 100% wool OD watch cap.  This is the Cap, Mechanic's, A-4.  An OD knitted wool cap without the small bill sewn in and the sides can be turned down over your ears for warmth.  This is a very comfortable cap that can be worn under the helmet in cold weather.

These are "Genuine government issue" "made to Department of Defense specification" according to the tag, and there's no seam down the back.  Considering that other vendors are selling theirs for $20 these are a great deal and will be great under a helmet.

These are GSA compliant and Made in USA