This Dentec Safety Specialists cover fits over the particulate pads on Comfort-Air series respirators. Box of 350. Dentec lists it as USA made, and their respirator plant is in Lenexa, Kansas.
A cover, holder, or retainer does no filtering itself, but that does not put it outside the approval. NIOSH approves the whole respirator, and the approval label spells out which parts the configuration allows, so leaving one out or swapping in something the label does not name can take the assembly out of approval. Check the part number against the label for your respirator. The filters these hold are under respirator cartridges and filters, and the program side is OSHA 1910.134.