The original yarn was Sirdar Yo-Yo, which is now discontinued, so a substitute will be needed.
Yarnsub.com describes this yarn as a Boucle yarn, 74% acrylic, 14% wool, 12% polyester
Tension given in the pattern: 17 sts and 24 rows to 10cm (4"), over 2 x 2 rib, using 4.5mm.