Sigma EM-140 DG E0-ETTL-II RIng Flash for Canon with Soft Case, for Parts | eBay
Sigma EM-140 DG Macro Ringlight Flash for Canon EOS F30101 B&H
Amazon.com : Vivitar 6000AF TTL Auto Focus Macro Ring Flash for Nikon, Canon, Pentax & Minolta Cameras : On Camera Macro And Ringlight Flashes : Electronics
File:Sigma 150mm with Canon MT 24-EX.jpg - Wikimedia Commons