You will need 4 buttons, approximately .75” (18 mm) each. Rowan used grey corozo buttons #TGB2869 from Textile Garden in the UK.

Finished measurements
Chest circumference: 33.25( 37.25, 41.25, 45, 49, 53, 57 60.75, 64.75)“ 84.5( 94.5, 104.5, 114.5, 124.5, 134.5, 144.5, 154.5, 164.5) cm
Finished length: 19.759 20.5, 21.25, 22, 22.75, 23.5, 24, 24.75, 25.25)” 50( 52, 54, 56, 58, 60, 61, 63, 64) cm

Yarn used:
Rowan Pure Alpaca
Shade 126 Khaki - 7(8, 9, 10, 11, 12, 13, 15, 15) balls