Features:

• E-TTL operation with all EOS digital SLRs; PowerShot G2, G3, G5, G6, and Pro1; and the following EOS film cameras - EOS-1v, EOS-3, Elan 7N series, Elan 7 series, Elan II series, Rebel T2, Ti, K2, GII, G. / TTL operation with all other 35mm EOS SLRs, and Canon T90
• Guide Number 190 (at ISO 100, feet) / 58 (meters); flash head at 105mm zoom setting
• About 100 to 700 Flashes with fresh AA-size alkaline batteries / Uses Four AA-size batteries - alkaline, lithium, or rechargeable Ni-MH usable (we advise using optional rechargeable batteries for long lasting service)
• AutoFocus Assist Beam
• Fourteen Speedlite Custom Functions built-in; set on Speedlite's LCD panel

Editor Reviews:

Product Description:
Further development of Canon's flagship Speedlite has led to the production of the 580 EX II. This is the premier Speedlite for all photographers, including professionals. Newly designed to match with the EOS-1D Mark III in terms of improved dust- and water-resistance, body strength, and the ability to control flash functions and settings from the camera menu (EOS-1D Mark III only). Other features include improved communication reliability through its direct contacts, and recycling time is both 20% shorter than the 580EX and is completely inaudible. Optional External power supply - compatible with Dust- and water- Resistant External Power Pack, Canon battery pack CP-E3 and Transistor Pack E Unit Dimensions - 3.0 x 5.3 x 4.5 inches /76 x 134 x 114mm; Weight - 13.2 oz./375g, without batteries (4 AA alkaline batteries add 3.5 oz./100g)

Rating : - Excellent product
Works well with my old 420EX used as a slave. That gives a new dimension of creative photography.