Microlink extensions, also known as micro ring, micro bead, I-tip or cold fusion extensions, are a way of adding length and volume to your hair without heat or glue. Small strands of hair are threaded through tiny metal rings alongside your own hair, and the ring is clamped flat with pliers to hold the extension in place. Because nothing is bonded, melted or stuck to your hair, many people see this as one of the gentler fitting methods, and the rings can often be reused when your extensions are moved up.