This cowl is reminiscent of the turtle neck style. The cowl is made in a repeating “rib” pattern for a very stretchy fabric. The edges can be left unfinished, or can be edged with single crochet stitches.
I have called this technique “bind-off ribbing” and have also made sleeve cuffs, a neck of a sweater and a set of wrist warmers using this technique because it is so stretchy, unlike many Tunisian ribbing options.
The pattern can be adapted for other sizes by changing the stitch count and number of ribs/rows. Included in the pattern is how to seam the cowl at the same time as completing the final row for an almost invisible seam.
A modified simple stitch provides a firmer back and more structure to this cowl.
This cowl requires more than one ball of Shiver, but you can make a set of wrist warmers with the remaining yarn.
There is also a scarf pattern called Tunisian Ribbed Scarf which uses this technique.