A baby sling or baby carrier is generally made of soft fabrics that wrap around the chest. They provide comfort and support for the baby and allow the parent or carer to keep their hands free as they go about their everyday tasks. There are a wide variety of carriers available from wraps and ring slings to soft structured carriers and mei tai’s. The use of a baby sling is called babywearing. Types Ring slings These are baby carriers that use dynamic tension, a length of cloth and metal (such as aluminum) or nylon rings. One end of the cloth is sewn to two rings. The cloth wraps around the wearer's body from shoulder to opposite hip and back up to the shoulder, and the end is threaded through the rings to create a buckle effect. The baby sits or lies in the resulting pocket. Once a sling is threaded, it can be taken off and put back on without rethreading. A threaded sling forms a loop of cloth. The wearer can put one arm and the head through the loop of cloth to put the sling back on. When the baby is in the carrier, the baby's weight puts tension on the fabric, and the combination of fabric tension, friction of fabric surfaces against each other and the rings combine to "lock" the sling in position. This type of sling can adjust to different wearers' sizes and accommodate different wearing positions easily. The wearer supports the baby's weight with one hand and uses the other hand to pull more fabric through the rings to tighten or loosen the sling. Ring slings may be padded or unpadded at the shoulder, have padded or unpadded edges or "rails", and the "tail" of the sling may be open or closed. Some "hybrid" ring slings have curved seats sewn into the body, similar to the seam in a pouch. Ring slings are most closely related in use to the Mexican rebozo, the rings take the place of the knot. Variation is also found in how the rings attach to the cloth, commonly referred to as "shoulder style". Basic shoulder styles include gathered, pleated, "hot dog" or "center fold", pouch-style (folded in half) and many variations. Ring slings are highly adaptable and most care givers can wear a "one size fits most" size. As long as the tail is about 8" long a ring