For sizes XS (S, M, L) you will need 7 (9, 12, 15) skeins of Tilli Tomas Elsie (33% Merino, 33% Silk, 33% Milk Protein; 140 yds/50g).
Suggested needles are US 6 (4mm) Needles. You will also need 2 Stitch Holders.