The Speedlite 600EX II-RT delivers impressive power, responsive performance and advanced, wireless communication for those who demand the very best in flash photography. Featuring improved continuous performance up to 2.0x* faster than its predecessor, the Speedlite 600EX II-RT performs at a phenomenal speed, and reliably at that - new Quick Flash settings and a flash-readiness indicator help ensure priority shutter operation, even when the flash isn't fully recharged. It's also built for fast, convenient use virtually anywhere for any situation, with improved combination button and dial controls, a refined dust- and water-resistant body and new accessories tailor-made for enhanced lighting effects. For speedy and comprehensive flash photography on the go, the Speedlite 600EX II-RT delivers portable, professional performance with ease.