Amazon.com : Sigma EM-140 DG Macro Ring Flash for Canon SLR Cameras : On Camera Macro And Ringlight Flashes : Electronics
Amazon.com : Nissin MF18 for Nikon Macro Ring Flash - TTL Flash with Soft Diffuse Light and Precise Control for Professional Macro Photography, 1/1 to 1/1024 Power, User Friendly Controls : Electronics
SIGMA EM-140 DG Macro Flash for Canon - Newegg.com