You will need 4 buttons, approximately 3/8” (10 mm) each. Rowan used grey mother of pearl buttons #TGB4679 from Textile Garden in the UK.

Finished measurements:
Chest circumference: 32( 35.75, 39.5, 43.5, 47.25, 51, 55, 58.75, 63.5)“ 81( 91, 100.5, 110.5, 120, 129.5, 139.5, 149, 161) cm
Finished length: 18( 19, 19.75, 20.5, 21.25, 22, 22.5, 23.25, 23.5)” 46( 48, 50, 52, 54, 56, 57, 59, 60) cm
Sleeve seam: 4.25( 4.75, 4.75, 5, 5, 5, 5, 5, 5)“ 11( 12, 12, 13, 13, 13, 13, 13, 13) cm

Yarn used:
Rowan Summerlite 4 Ply
A. 419 Duck Egg - 5(6, 7, 7, 8, 9, 10, 10, 11) balls
B. 429 Navy Ink - 1 ball for all sizes