100-400mm telephoto zoom lens with f/4.5 maximum aperture for Canon SLR cameras. 2 Image Stabilizer modes make it easy to capture far-off action or close-in portraits. Flourite and Super UD-glass elements largely eliminate secondary spectrum. Compatibility with extenders 1.4x II and 2x II; 5.9-foot close focusing distance. Measures 3.6 inches in diameter and 7.4 inches long