Long Johns with fly 200 are circular-knitted long johns which therefore have no lengthwise seams. Due to our unique circular knit, the long johns have a comfortable fit and do not chafe the skin when you move around. The garment is made from Woolpowerâs own fabric Ullfrotté Original 200, which was developed in the 1970âs. Wear them next to your skin or as an insulating second layer. A gusset in the back ensures optimal comfort without feeling tight. Knitted-in cuffs and waistband.