Honeywell™ RD40 Plastic Filter AB2P3 Activated and impregnated charcoal without chromium, 106 mm OD, 300 gr Air Purifying Respirator Cartridges and Filters | Fisher Scientific
Spasciani RD40 filters (40 mm universal thread) - SafetyGas
Full face respirator - 40mm gas mask X-plore 6300 | SafetyGas