The Savage Macro Art Variable Auto-Extension Tube (for Canon EOS) combines the three most common automatic extension tubes into one integrated range. Conveniently adjust magnification strength without changing tubes to proficiently capture fine detail with ease. This macro extension tube offers a variable extension range of 40-56mm for fine-tuned control of the lens-to-sensor distance. It also maintains full autofocus and exposure metering. The bayonet mount is constructed from durable metal and the all-metal tubes interior is matted to prevent unwanted reflections or flare.