You'll need:

Measurements:
Approx 56cm – 58cm fits most female heads.

Special Abbreviation :
Trf – Treble front
Yarn over, insert the hook from front to back and out through the front again around the post of the treble of the row below, hook yarn and pull up a loop (3 loops on hook) (yarn over and draw through 2 loops) two times. Make 5 ch, sl st in the first ch to make a loop.
1st rnd: Ch 3, 11 tr in ring. End with a slst to top of ch 3 (12 tr made).
2nd rnd: Ch 3, work trf around post of ch 3 of rnd below, *tr in next space and work trf around next tr (increase made) repeat from * around, end slst to top of ch 3 (24sts, 1 tr and 12 trf).
3rd rnd: Ch 3, tr in next space and work trf around post of next tr * [tr in next tr], tr in next space and work trf around post of next tr. Repeat from * around, end slst to top of ch 3 (36 sts).
4th rnd: Ch 3, tr in next tr, tr in next space and work trf around post of next tr, * tr in each of next 2 tr, tr in next space and work trf around post of next tr. Repeat from * around, end slst to top of ch 3 (48 sts).
5th, 6th, 7th, 8th, 9th, 10th,11th & 12th rnds: Repeat round 3, increasing one stitch between trf each row (see [ ] of round 3 until there are 11 sts between each post.
13th rnd: slst into next tr. Ch 3, Skip next tr, tr in next 9 tr, trf around next tr. * skip next tr, tr in next 10 tr, trf around trf from row below* Repeat between *’s around. Join with a slst to the top of ch 3.
Continue decreasing in each round in this manner until there are 3 tr between trf posts.
Next 3 rnds: dc around.
Fasten off and sew in loose ends with the yarn needle.