 "Canon Speedlite 600EX II-RT"@en II-RT 1177C002 - Studio Depot"@en
"
Effective flash range of 2.3 to 77.4'
Exposure compensation of ±3 EV in 1/3 or 1/2 step increments
Light Distribution settings allow for Standard, Guide Number Priority, and Even Coverage
Radio master and slave functionality 
Use in up to 15 flash setups
10 custom Functions and 8 personal Functions 
LCD panel on rear for viewing and changing settings
AF assist beam with range of up to 13.1'
Fresh batteries will provide approximately 180 full-power flashes
"@en 
 Compatible Cameras Type-A EOS cameras (E-TTL II/E-TTL autoflash) Type-B EOS cameras (TTL autoflash)  Guide Number Approx. 49.2 ft/15m at ISO 100 Number of Flashes Approx. 100 - 700 flashes Recycling Time Nominal Flash: 0.1 - 5.5 sec Quick Flash: 0.1 - 3.3 sec  Flash Range Effective flash range with EF 50mm f/1.4 lens at iso100 Normal: Approx. 1.56 - 91.2 ft/0.5-27.8m Quick Flash: Approx. 1.6 - 48.6 ft/0.5-14.8m High-Speed Sync: Approx. 1.6-48.2ft/0.5-14.7m  AF Assist Beam Infrared AF-assist beam TTL second image formation phase-difference AF Support 1-65 AF points Phase-difference AF during viewfinder shooting Quick mode during Live View Shooting or movie shooting Effective Range: At center: 2.0 - 32.8 ft/0.6-10m At periphery: 2.0-16.4 ft/0.6-5.0m  Custom Functions 15 Functions 6 Functions  Power Source Four AA-size/LR6 alkaline or AA/HR6 Ni-MH batteries External Power Source Compatible (Compact Battery Pack CP-E4N recommended) Dimensions 3.10 x 5.64 x 4.83 in/78.7 143.2 x 122.7mm Weight Approx. 15.34 oz/435g
 "Canon Speedlite 600EX II-RT - hot-shoe clip-on flash" Flashes & Accessories CDW.com " Canon flash 1177C002 Lights
"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 - 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 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." 