Super 500mm/1000mm f/8 Manual Telephoto Lens for Pentax K-S2, K-S1, K-500, K-50, K-30, K5 IIs, K-7, K-5, K-3 II, K-2, K-X, K20D, K100D, K110D and K10D Digital SLR Cameras Super 500mm achromatic refractor telephoto lens 2x Teleconverter doubles the power of your lens to 1000mm. High index, low-dispersion multi-coated HD optical glass to reduce flare Built-in tripod collar for improved lens Balance Kit includes 500mm super telephoto preset lens, 2x doubler, t-mount, UV filter, lens hood, cleaning pen, dust blower, 47th Street Photo microfiber cleaning cloth