The YN Extender EF 2x III lens is designed to be matched with the Canon white telephoto lens,more suitable for the Canon white telephoto lens than YN 2.0 II teleconverter. This YN extender EF 2x III lens lets consumers focus in on subjects located at far-off distances. With this capability, this 2x lens does many jobs in one so users don’t have to keep switching between so many lenses. Each element in this YN camera lens has a Super Spectra coating, which is designed to minimize flare and ghosting artifacts. This lens offers owners a higher, more precise auto focus to create sharp, clear photos. Dust and water resistant, this lens lets users photograph in tough conditions. * *Although the lens has some waterproof performance, but if shooting in the rain, please try not to get wet. Features: 1. The function of this product is to extend the Canon lens’ focal length by 2 times. 2. Especially designed for the Canon white telephoto lens. 3. The optical performance is on a par with Canon Extender’s. 4. Uses two pieces of ultra-high refractive index lenses, which greatly improves the optical effect. 5. 5 groups 9 pieces of glasses construction, each piece of glass uses multilayer coating, which improves the lens’s transmittance, reduces the stray light, optimizes the optical quality. 6. This lens uses the matching design for Canon EF 70-200mm F/2.8L IS II USM and it can be used with Canon EF 70-200mm F/2.8L IS II USM perfectly. Specifications: Mount: EF mount(Electronically controlled) Lens construction: 9elements in 5 groups Dimensions(max.dia. ×length): 55×73.9mm Weight: approx.342g Please read the instruction manual carefully before uing the product. Package Includes: 1 x YONGNUO Extender EF 2X III 1 x Front Cap 1 x Rear Cap