Ideal for press, sports and nature photography, the extender increases the focal length of Canon L-series telephoto or telephoto zoom lens\' by a factor of 2x, with higher AF accuracy and improved communication between camera and lens. Benefits Extends the master lens focal length by 2x Compatible with L-Series telephoto and telephoto zoom lenses Optimised lens coatings Improved communication between lens and camera Highly resistant to dust and water Outstanding image quality Compatibility EF 600mm f/4L IS USM EF 400mm f/2.8L IS III USM EF 600mm f/4L IS III USM EF 800mm f/5.6L IS USM EF 500mm f/4L IS II USM EF 500mm f/4L IS USM EF 400mm f/5.6L USM EF 400mm f/4 DO IS II USM EF 400mm f/4 DO IS USM EF 600mm f/4L IS II USM EF 135mm f/2L USM EF 300mm f/2.8L IS II USM EF 300mm f/4L IS USM EF 200mm f/2L IS USM EF 200mm f/2.8L II USM EF 300mm f/2.8L IS USM EF 400mm f/2.8L IS USM EF 400mm f/2.8L IS II USM EF 180mm f/3.5L Macro USM EF 70200mm f/2.8L IS II USM EF 70200mm f/2.8L IS III USM EF 70200mm f/2.8L USM EF 70200mm f/4L IS USM EF 70200mm f/4L IS II USM EF 70200mm f/4L USM EF 100400mm f/4.5 5.6L IS II USM EF 100400mm f/4.5 5.6L IS USM EF 200400mm f/4L IS USM Extender 1.4x