You will need 5(5, 5, 6, 6, 6) buttons. Sirdar used their buttons # B5611-0785. You will also need a stitch holder.

Finished measurements:
Chest circumference: 18(20, 21.25, 22, 23.25, 24)“ 46(51, 54, 56, 59, 61) cm
Finished length: 9.75( 10.75, 11.75, 12.5, 13.5, 14)” 25( 27, 30, 32, 34, 36) cm
Sleeve to armhole: 6.25( 6.5, 7, 8, 8.75, 9.75)“ 16(17, 18, 20, 22, 25) cm

Yarn used:
Sirdar Snuggly Cashmere Merino
Shade 467 Silver - 4(4, 5, 5, 6, 6) balls