“First impressions of a woobie are usually that there is no way this lightweight, flimsy thing will keep me warm. However first impressions are often wrong, not only will this quilt/blanket/sleep pad keep you warm it is remarkably robust. I have used mine in maimais on cold nights and been toasty, I used the one from my vehicle emergency kit when the car broke down and I spent a night 'surprise camping' on the side of the road, and I've snuggled up in one on the front porch while we watched the stars. They also make great picnic blankets and can be used as padding around breakable items (glass lanterns, electronics etc) in your emergency kit.
The reason there is no head hole, although having a seamstress or tailor add one is a popular modification, is that they are designed to be tied into the poncho with the attached straps and fashioned into a summer weight sleeping bag . Other mods include adding grommets to the corners to help turn it into a hasty shelter, adding two sided or 'gypsy head' press studs along the edges to allow for a more firmly connected yet less drafty sleeping bag or for joining two or more woobies together, adding open ended type zips or sewing olive drab cotton tape along the edges (sew across the tape at 3 to 4 cm intervals) to allow for paracord to be threaded through the tape, again for joining or forming a sleeping bag.”