Tried Castelli leg warmers but at 5'8" the mediums were too long but the smalls were too tight. These were also the thinner material as mentioned in another post above. So last month I got Verge brand knee warmers off of eBay. These have a light fleece inside. They fit great. They also do well underneath tights; since the knee warmers stop mid-calf they don't interfere with the zipper on the tights. I'm a wimp in the cold so from about 41 or colder I've got the tights+warmers on.