Check the listing for details. AVON M50 gas mask filters sealed and new. Condition: New. Listed at 40.00 USD. Set of new and sealed filters for the Avon M50 gasmask- Quartermaster Supply has been in business for 26 years, buying and selling, quality military surplus. Specializing in hard to find items and quality military equipment. We only carry the real deal US military issue gear- period. The owner is a former Army enlisted man and military officer. School trained at NBC chemical warfare school, as well as small arms armorer school. Thanks for your interest- DerekSet of new and sealed filters for the Avon M50 gasmask- Quartermaster Supply has been in business for 26 years, buying and selling, quality military surplus. Specializing in hard to find items and quality military equipment. We only carry the real deal US military issue gear- period. The owner is a former Army enlisted man and military officer. School trained at NBC chemical warfare school, as well as small arms armorer school. Thanks for your interest- Derek