Amazon.com : Tronixpro 95mm Pro Series High Resolution Digital Ultraviolet UV Protection Filter for Sigma 150-600mm 50-500mm, Tamron SP 150-600mm f/5-6.3 Di VC USD Lens + Microfiber Cloth : Electronics
Amazon.com : 52mm UV Filter for Canon, Olympus, Pentax, Sony, Sigma, Tamron Digital Cameras and Camcorders : Electronics
SIGMA BRAND 52mm SGV WR UV WATER REPELLENT FILTER NEW in FACTORY BOX & CASE | eBay