Promaster Spectrum 7 Extension Tube Set for Nikon F wind This is a standard waist-level

This is a standard waist-level viewfinder for the Mamiya RB67 medium format SLR camera

and it includes two comparator discs if you're planning to use it as a pocket comparator

Provides a 25mm extension for FD lenses

) If you only want to carry one lens for pretty much everything

Promaster Spectrum 7 Extension Tube Set for Nikon F wind This is a standard waist-levelA set of three extension tubes for Nikon F mount: 12mm, 20mm, and 36mm. These tubes have the electronic contacts necessary to maintain autofocus and autoexposure capabilities. If you're curious about dabbling in macro work, this is an inexpensive way to get started. Good working order, light cosmetic wear. Includes rear cap; lens and camera sold separately.