A long piece of fabric that fits the baby to the desired position with knots. There are many different qualities and types of fabric (thin, thick, elastic…). The appropriate fabric for wraps is the one that stretches only in its diagonal way (not in a transversal or vertical way), giving a lot of support and adaptability to both the carrier and the baby. It can be used as from new-born until the carrier and the baby want, and in many different positions (cradle, ahead, to the back and to the hip).
They are comfortable and practical, though they need a bit of practice with the knots.