This easy ear warmer is suitable for children to adults. From the right side, the pattern is two purl rows and 4 knit rows, with a single stitch garter border on each edge, like ribbing.

It is highly customizable:
Choose whatever yarn you want and the appropriate needles.
Check your gauge.
Adjust the width by changing the number of stitches you cast on.
Adjust the length by stopping when you reach the desired circumference.

19 grams of Woolease with size 8 needles for 21 inch prototype