One 7.5 mm needle is used.

This is Pattern 14 in Holiday Knitting, Volume 8.

Measurements
To fit bust sizes
80/85, 90/95, 100/105 cm
(32/34, 36/38, 40/42 in)
Finished measurement
100, 110, 120 cm
(40, 44, 48 in)

Each source has its own recommended yarn. The following is from the Richard Poppleton version

Materials
Rio with Mohair
Colour A: 6, 7, 8 X 25 gram balls
Colour B: 5, 5, 5 X 25 gram balls
Shirring elastic, if required.