7 combinations in total. Combined of 3 tubes with different
length of: 13mm, 21mm, 31mm.
Mount the tubes between your lens and camera to get your choice
of macro ranges.
It moves the lens farther from the film or digital sensor. The
farther away the lens is, the closer the focus, the greater the
magnification. This extension tube will not affect image quality as
there is no optics inside.
Designed with all the circuitry and mechanical coupling to
maintain auto focus and TTL auto exposure with Canon DSLR