A ring sling is a length of fabric with a pair of rings sewn in to one end. The other end of the fabric is threaded through the rings to make an adjustable pouch to sit your child in.
Possibly the most versatile “quick-ups” carrier in existence, the same ring-sling can be used from newborn to toddler and beyond. BUT there’s a steepish learning curve to get the adjustability/comfort/safety balance right.
We love ring slings, we have lots and lots and get all excited when we are asked to help people learn to use them.