The pamphlet I have has mixed up the gauge for this balaclava and the gauge for the cap. I have changed them over.

Measurements
Width round head
18, 20, 22 inches

Each pamphlet has a different set of recommended yarns. The following are from the Midgley and Catton version.

Materials
MIDGLEY AND CATTON Double Knittings
Homestead with Nylon or Tulip Triacetate Nylon
3, 4, 5 balls or hanks
Stitch holders
Button.