With the PressToCheck™ filters you can instantly check that you have the correct seal every time. Award winning - Winner of the BSIF Product Innovation Award. See Respiratory Director Matthew Judson accept the award on behalf of JSP Ltd. Comfort, FIT IT!, Don the Mask - Put the straps and harness over your head and pull the straps to a suitably tight and comfortable fit. PRESS IT!, PressToCheck™ - Press the front and backs of both filter covers together to stop air from entering through the filters. CHECK IT!, Inhale - No air should come through the mask. Adjust the mask and repeat until it doesn't. Release when seal is made.