The MR-14EX II Macro Ring Lite Flash from Canon is designed for use with a Macro lens for close-up photography. With a guide number 34' at ISO 100 per side, its twin tube design allows each flash tube to fire independently, or simultaneously to provide a combined guide number of 46' at ISO 100. White LED focusing lamps and two types of modeling lights allow for accurate previewing of the light's effect. An illuminated dot-matrix LCD screen lets you make adjustments to the flash in both bright- and low-light situations. The MR-14EX II has 12 custom functions, and supports wireless E-TTL when linked with one or more Speedlite 600EX-RT flashes. The ring flash can be powered by 4x AA batteries or an optional CP-E4 battery pack.