From the Website:
87.5% Lambswool/12.5% Cashmere
Supersoft Cashmere was created by Rennie to produce a yarn which retains the three-dimensional lofty look of a Shetland/Lamsbwool garment but with an even softer feel. The balance of cashmere and fine mircon lambswool created by Rennie is a perfect mix to produce the softest Scottish yarn at the best possible price. Ideal for both knitting and weaving, Supersoft Cashmere is available as 50g hand knitting balls (Double Knit).