Double knee for super durability. Extra pocket on leg. Wrinkle resistant and stain release. Permanent crease (not available on washed colors). Washed colors are silicone washed. Loose fit. Convenient extra pocket on leg. 8.5 oz. twill fabric, 65% polyester/35% cotton. No iron, stain release fabric with crisp permanent crease means they look great wash after wash. Tough tunnel belt loops.