P1 R D particulate filter for protection against non toxic dusts, fumes and water/oil based mists/aerosols 4 x WELRevolutionary EasyLock filter system with no additional clips or holders. Different gas and particulate filters can be combined. EasyLock® particulate filters can either be connected to the EasyLock® gas cartridges or directly with the mask body.Any combination of filters possible, simply click together, there is no need for additional clips or filter holders. , EN143:2007, EN14387:20081 BOX = 20 FILTERS (NOT PAIRS)