Right now there are 50 deals from Amazon Resale, formerly Amazon Warehouse Deals, in Industrial & Scientific › Filtration › Compressed Air Treatment. These are inspected returns and open-box items that Amazon sells and ships itself. WarehouseHunter puts each one next to its current new price, so you can see what you save at a glance.
Brands with the most offers here: Milton, Ingersoll Rand, NANPU, TAILONZ PNEUMATIC, SNS, VEVOR, Element, Graco. Every item is a one-off, so the stock moves all day and new deals keep arriving.