Product Description Item Number | 7580P100North Safety P100 Particulate Respirator Cartridges 1 Pair of P100 Particulate Cartridges Covers provide 99.97 Filter efficiency North offers a complete line of cartridges and filters for the North 5500, 7700, 5400 and 7600 Series face-pieces. All cartridges and filters listed below are interchangeable with any of these masks. Filters for Limited Use respirators, canisters for gas masks, and PAPR cartridges are listed in this catalog with those products. 1 pair per package All North Cartridges are interchangeable for the North 5400, 5500, 7600 and 7700 Series Face-pieces.OSHA's Standard for respiratory protection, 29CFR 1910.134, requires Employers to implement a change schedule for all vapor and gas cartridges when there isn't an end-of-service life indicator on the cartridge. This schedule must be site specific and take into consideration worksite humidity, worker breathing rate as well as contaminant concentrations.