52MM UV Filter + 52mm Tulip Lens Hood for Canon EF-S 24mm F2.8 STM, 52 mm Ultraviolet Filter & 52 mm Lens Hood Absorbs Ultraviolet Light - 3-Layer Multi-Coating - General Protective Filter Low-Profile Aluminum Frame - High-Transparency Optical Glass Tulip Lens Hood to Reduce Glare Maintains Exposure Levels - Brand New, Retail Packaging Look at your lens for the symbol  usually on the front or under the lens cap (under the cap will just be a number) the number next to it is the filter thread size.