70-200mm telephoto zoom lens with f/4 maximum aperture for Canon SLR cameras. Inner focusing system and ring-type ultra-sonic monitor for quick and quiet autofocusing. Compatible with same tripod collar (sold separately) as EF 300mm f/4L USM lens. 3.9-foot close-focusing distance; supports use of circular polarizing filter. Measures 3 inches in diameter and 6.8 inches long; weighs 25 ounces