You will need a cable needle.

You will also need:
Size US 3 (3.25 mm):

• Circular needle no longer than 16” (40 cm)
• Circular needle no longer than 28(32, 36, 40, 44, 48, 52, 56, 62)“ 70(80, 90, 100, 110, 120, 130, 140, 150) cm
• Set of four double pointed needles

Size US 5 (3.75 mm)

• Circular needle no longer than 16” (40 cm)
• Circular needle no longer than 28(32, 36, 40, 44, 48, 52, 56, 62)“ 70(80, 90, 100, 110, 120, 130, 140, 150) cm
• Circular needle no longer than 44( 48, 52, 60, 64, 74, 78, 86, 90”) 110( 130, 140, 160, 170, 190, 200, 220, 230) long

Finished measurements:
Chest circumference - 32( 35.5, 39.75, 44, 48.25, 52, 56, 59.75, 64)“ 81( 90, 101, 112, 122.5, 132, 142.5, 152, 162.5) cm
Finished length - 20.5( 21.25, 22, 22.75, 23.5, 24.5, 24.75, 25.5, 26)” 52( 54, 56, 58, 60, 62, 63, 65, 66) cm

Yarn used:
Rowan Summerlite DK
Shade 487 Lavender Mist - 7(8, 9, 10, 11, 12, 13, 15, 16) balls