This face mask has an opening for an instrument mouthpiece to fit through.
4 pieces of 8 ½” x 3 ½” cotton fabric
4 6” pieces of light weight elastic
Using a ¼” seam allowance, sandwich elastic between 2 pieces in the corners, 2 per mask half. Sew around, leaving an opening, and being sure not to catch elastic in seam. Clip the corners without elastic. Turn inside out and press. Topstitch around.
Overlap the 2 mask halves by about ½”, with the elastic being on the outer corners. Make 2 ½” tucks on each side. Sew down both sides to secure the tucks.
Making sure the mouthpiece fits through the opening, tack the overlap together on both sides of the mouth. Tie the elastic to fit the person.