The 3M 502 filter adapter allows you to add a P100 particulate filter on top of a 3M chemical or organic vapor cartridge. The 502 is compatible with the 3m 6001, 6003, 6004 and 6006 cartridges that we have listed on our site. The P100 rated 2000 series filters and the P100 rated 7093 filters will both fit adapter. Simply snap the 502 adapter on top of a cartridge and then attach a filter to it with a 1/4 tur. SOLD PER BOX OF 20 Part Number : 502