The part of camera mount and lens mount are both made of high quality brass, while the tube is made of high quality ABS plastic Shortens minimum focusing distance of lens for macro photography, convert almost any lens into a macro lens, save your cost of buying an expensive macro lens Full Autofocus and auto exposure Compatibility Extension tubes of 12mm, 20mm and 36mm lengths can be used individually or in any combination of the three for greater magnification Fits Nikon F-mount DSLR cameras and all F-mount lenses