Helmetliner Original Pattern designed by Bonnie Long Materials: Any soft, worsted wool yarn that will knit to gauge, such as Cascade 220 . Only 100% soft wool yarn will be accepted, because our ground forces are not allowed to wear synthetic fibers. Wool is inherently non-flammable and won’t melt against the skin in the event of an accident and is warm even when wet. Colors: Black is preferred but charcoal, brown, tan, gray or combinations of these colors are also allowed by our Armed Forces. Gauge: 4.5 stitches per inch in stockinette stitch To date, more than 23,000 heltmetliners have been shipped overseas (by Citizen Sam). There are currently more than 200,000 troops in overseas theaters where they are subjected to sub-zero wind chills during the winter and extreme heat in the summer. Finished items may be sent year-round to Citizen SAM, PO Box 10565, Peoria, IL 61612.