Choosing the Correct Mask Size
We recommend taking exact measurements using the method described below to determine the correct mask size for your facial structure.
Measure from the centreline of your face at your mouth to at least 1 inch (2.5 cm) past the outside corner of your mouth (you might want to ask a friend to assist you). The outer edge of the Training Mask should sit against your face at 1 to 1.5 inches (2.5 to 3.8 cm) outside the corner of your mouth.
Double the measurement you have taken and match to the best fit from the below:
Large: 5 inches (12.7 cm)
Medium: 4.5 inches (11.4 cm)
Small: 4 inches (10.2 cm)
Below is a general guide based on body weight (note that facial measurements are more accurate for ensuring correct fit):
Large: 250 - 300lbs
Medium: 150 - 249lbs
Small: 100 - 145lbs