Traditionally used in denim up until the late 1970s, ring spun denim was later replaced by more inexpensive Open End yarns. Ring-spun yarn creates unique surface characteristics in the fabric, such as unevenness, giving jeans an irregular authentic vintage look. Greater strength and softness is also achieved. Heddels
Ring-spun yarn is created by continuously rolling and thinning fibers into shape. It takes five times longer to create than open end yarn; however, it produces a much softer and stronger yarn. Ring-spun yarn is also thought to have more character as it is more uneven and contain slubs (thicker areas along the yarn). Heddels