This Mosaic cowl requires 2 highly contrasting skeins of DK weight yarn. It is designed to be knit flat with increasing stitches on one side then seamed at the corners to wear around your neck.
One size fits all, but if you prefer the cowl to fit closer to your neck seam the corners more.
Required needles US size 6 -24” circular or whatever size you need to reach the 5 stitches = 1-inch gauge.

The model is wearing the cowl made with 2 contrasting colors of KS Fiber Arts Silky Yak DK yarn 60/20/20 Superwash wool, Silk, Yak blend that feels very luxurious around your neck. I highly recommend you use a very nice, soft fiber to wear close to your neck.