The Nikon AF-S Teleconverter TC-20E III doubles the effective focal length of select compatible NIKKOR lenses, offering an affordable and portable gateway to extend telephoto reach; ideal for sports shooting, wildlife, surveillance and more.FEATURES: Enhanced Telephoto Versatility - Affordable and portable gateway to extend telephoto reach; ideal for sports, wildlife, surveillance and more. 2x Optical Conversion Factor - Doubles the focal length of select compatible NIKKOR lenses. Aspherical Lens Element - Virtually eliminates coma and other aberrations, especially at wide apertures. Nikon Integrated Coating (IC) - Enhances light transmission efficiency, improves color consistency and reduces flare. Advanced Optical Design - 7 elements in 5 groups optimized for use with FX and DX digital SLRs, engineered to meet the needs of professional photographers.