Uvex silv air c ffp123 pre formed masks withwithout valve white uvex 8732310 this pack of 15 pre formed masks from uvex have been designed with a valve and include the following features the 360deg exhalation valve considerably reduces breathing resistance and build up of heat and moisture in the maskcomfort sealing lip the soft sealing lip guarantees a secure comfortable sealed positioning of the maskcomfort nose clip the mask is fitted with a high quality nose clip making it