This new TC-X20 Tele converter is designed exclusively for select Nikon mount Tamron lenses. This tele converter increases the maximum focal length while nearly maintaining the MOD, so the magnification ratio during close focusing is enhanced. It also features Tamron’s sophisticated eBAND Coating for eliminating ghosting and flare. Both autofocus and VC features are retained with the compatible lenses. Moisture-Proof and Dust-Resistant Construction with a sturdy, durable barrel design for is perfect for use with these larger lenses The bayonet mount made of brass on the camera side and stainless steel on the lens side to ensure excellent durability even with repeated mountings and detachments. Technical Specifications: Model Name TC-X20, Magnification 2.0x, Optical Construction 9 elements in 5 groups, Maximum Diameter for Nikon Ø62.3mm, Entire Length 65mm, Weight for Nikon 10.8 oz., Accessories mount cap, rear cap, lens case.