This cowl is worked in rounds following a cable pattern (written and charted), its level of difficulty is not high, but a little experience is necessary.
The cable pattern repeats 8 stitches and 8 rounds; if you want to modify the circumference of the cowl, you only have to add or remove a number of stitches multiple of 8.
If you want it longer, repeat this sequence of 8 rounds as many times as you want.
Please note that any of these modifications will change the amount of yarn required.

Yarn
Katia Merino Aran (100g/155m) 1 ball, sample color 69 gray. Or any yarn with similar weight

Needles and notions
-6mm circular needles (50cm / 20in)
-1 stitch marker and 14 extra markers to separate chart repeats
-Tapestry needle
-Auxiliary needle
-Scissors

Gauge
20 sts and 19 rounds over cable stitches

Measurements
After washing and without stretching: 60cm / 24in circumference; 22cm / 8 ½ in length