You will need a circular needle in size US 6 (4.0 mm) . YOu will also need a D-ring and a button for fastening.

Finished measurements:
Bust circumference: 35.5( 39.75, 43.25, 47.75, 51.25, 55.5, 59, 63.5, 67.75)“ 90( 101, 110, 121, 130, 141, 150, 161, 172) cm
Finished length: 24.75( 25.5, 26.5, 27.25, 28, 28.75, 29.25, 30, 30.25)” 63(65, 67, 69, 71, 73, 74, 76, 77) cm
Sleeve to underarm: 17.75(18, 18, 18.5, 18.5, 18.5, 18.5, 18.5, 18.5)“ 45(46,46, 47, 47, 47, 47, 47, 47) cm

Yarn used:
Rowan Alpaca Soft DK
Photographed in shades 203 Toffee and 222 Stone - 11(12, 13, 15, 16, 17, 18, 19, 19) balls