From the website:

This skein is 100g of 100% superwash Blue Faced Leicester wool. This fine yarn has a lovely tight twist like many popular merino sock yarns, with the added benefit of the silken sheen and slight halo of Blue Faced Leicester. The yardage is 409 yards/374 meters per skein. The suggested gauge is 32 to 40 stitches per four inches on 2.00mm (US 0) to 2.75mm (US 2) needles.

This is a fine enough yarn to be suitable for lace projects as well as socks. The fineness of the gauge also ensures that any garment made from this yarn will remain light while also keeping the durability of similar popular tightly spun yarns.