Had the misfortune of ordering a 40-pack of filters in early January and fulfillment with the free shipping option took nearly a month, including several weeks waiting for my order to ship. Thought I had plenty of time but ran out and had to buy overpriced disposable KN-95 filters elsewhere to cover two weeks' of work. Still prefer the small filters to tossing away an entire face mask worth of material, just need to order much sooner or pay for faster shipping.