Written pattern for those who find it helpful:

Tie yarn onto hair tie, ch 1
R1: sc around hair tie (36-45), sl into 1st sc

R2: ch 3, 3 tr in every sc around, sl into 1st tr

FO, weave in ends

US abbreviations used: (sc - single crochet, tr - treble crochet, ch - chain, FO - fasten off, sl - slip stitch)