This pre-filter retainer from Dräger Safety is an accessory of full face masks and half face masks which have a bayonet filter connection. 

The retainer itself does not provide any form of filter protection but acts as a cap and holds pre-filters in place.  

In order to use the retainers you will require the use of a Drager combination filter and a pre-filter pad.

Please Note: This product comes in a set of 14 pre-filter-retainers.