P3 R D particulate filter against harmful and carcinogenic dusts, fumes and water/oil based mists/aerosols 20 x WEL Revolutionary 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. 1 BOX = 12 FILTERS (NOT PAIRS)