This oblong 502 adapter clips onto a 3M™ oblong organic vapor cartridge, and has a bayonet hole for attaching a round filter to protect the cartridge from becoming clogged with particulates in dusty environments.
Sold by the each.
All 3M facepiece respirators can be used with ANY of 3M's vapor cartridge and filter combinations —
• Vapor cartridges attach directly to the bayonet fitting on the mask
• White oblong filters are attach on top of the oblong cartridges by using a #501 adapter, which snaps onto the cartridge
• All round filters can be attached to a cartridge by using #502 bayonet adapter, which snaps onto the cartridge
• All round filters can also attach directly to a facepiece, without a cartridge, when vapor protection is NOT required, and only particulate protection is required