Option
For DSLR :
Canon : EF mount
Nikon : F mount
Sony : A mount
Pentax : K mount

For Mirrorless
Canon : EOS M mount
Sony : E mount
Olympus/Panasonic : Micro 4/3

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 does not affect image quality as there is no optics inside. In comparison, a close up filters are often blamed for degrading image quality.
There are no electrical contacts in the extension tubes. Exposure has to be adjusted manually. Aperture control is not available if you use a lens which does not allow you to manually adjust the aperture (without an aperture ring).