Following on from the Canon 580EX, the Speedlite 580EX II flash has new features that are designed to improve results with the latest digital EOS cameras. Retaining the guide number of 58, this flash comes with a sturdy, dust and waterproof case and electronic circuit improvement technology to speed up its refresh time by approximately 20%. The Speedlite 580EX II is a fundamental part of any Canon EOS flash system, destined for use on digital or traditional cameras and by both professionals and beginners.