Direct PDF link here.

This is not the balaclava style helmet liner with ribbing at the face and neck. The helmet liner pattern can be found here.

100% wool desired for military use. See pattern. Use size 7 or 8 needles as desired.

From the information available at the source, this appears to have been derived from the helmetliner pattern created by Bonnie Long, modified by Rachel Kristy. The name of who modified it to this form is not given at the site.