The Hankison E1-36 is a precision filter cartridge manufactured by Hankison, a brand under Spirax Sarco, primarily used for end-of-line treatment of compressed air systems. In Hankison's filtration classification system, "E1" represents Grade 1, the most efficient ultra-precision oil and odor removal (activated carbon adsorption) filter cartridge; while "36" indicates the corresponding filter housing flow rate specification.