I purchased 3 bags of filters (each bag holding 2 filters) for my own use recently and realized I wont be needing them since my friend and I will be splitting the use of his respirator/filters.  I bought these from a US seller.  These are not the cheap Chinese knockoffs.  They are original 3M 2091 filters.  Expiration: 2/2025.  You are purchasing one bag containing 1 pair of filters (2 filters).