Top of the line Canon Flash for SLRs
Newly designed 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.
Great price - £50 cheaper than the next best
EDIT - Thanks to 'edgeone' for 'Dont forget TDX-24R8 for an extra £5 off and topcashback / quidco for 3%'http://www.camerapricebuster.co.uk/prod330.html