This bind off is also known as the Invisible Ribbed Bind Off, Kitchener Bind Off or Grafted Bind Off. You can find it from many sources—here is my step-by-step photo tutorial version.
Using ins-and-outs that will be easily understood by those familiar with Kitchener Stitch (but you don't have to be to do it), this bind off makes a beautiful, stretchy finish for the top of any 1x1 ribbed edging. Cut yarn at about 4 to 5 times the circumference or length of the edge you will be finishing and thread onto a yarn needle.
The finished product looks like this:
This very detailed video includes an extra tip for working this bind-off in the round, plus a couple of "reading your stitches" tips:
The Sewn Rib Bind Off is used in the following patterns:
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