Full mask airtightness detection method

When selecting the full face mask, the user first needs to select a suitable mask according to the size of his head type. Secondly, adjust the middle and upper headbands to appropriate positions and loosen the lower headband. Hold both sides of the mask with both hands, hold your breath, close your eyes, and cover the chin with the chin, and both hands are back at the same time. Hold the opening strap firmly, wear the top cover from the bottom up, and tighten the headband so that the mask and the face do fit together, and then breathe deeply and open your eyes. In addition, when wearing a full face mask, care should also be taken not to allow the headband and hair to press in the mask fit frame or to allow the headband claw of the mask to bend into the mask.