The Fixation Masks by Shannon Dunbabin use Fixation, a stretchy cotton/elastic blend. Fixation I-cords make perfect ear straps! The elastic in Fixation helps to ensure a more secure fit. 

The pattern is also available as a double layer which includes an opening to allow a filter. The pattern for the double layer is available here.

The masks are knit using size US 4 needles. 

This pattern is available as a PDF download.