Help from Nikon gurus??

[pphuang]

I needs some help indentifying this piece of equipment -

It looked interesting and was cheap, but now I'm trying to figure out what it is and how to use it. 😉 Is it an extension tube of some sort? There are no glass elements within the thing...

Thanks!!

 

[Gumby]

It certainly does look like an extension tube!

EDIT:

see http://www.mir.com.my/rb/photography/hardwares/classics/nikonf2/macro/index1a.htm

Here's what a guy on ebay says about the same item that he has for sale...
The Nikkor M extension tube was initially offered for the first Micro-Nikkor 55mm f/3.5 lens, and produced a macro ratio of 1:1. The rear mount of the extension tube is Non-AI, but will increase magnification on all Nikon lenses (Both AI & Non-AI).

 

[retro]

The Extension Tube "M" was for the first version of the
Micro-Nikkor 55mm f/3.5 which was a preset lens. Then Nikon
made an M2 tube for the 2nd major version of this lens which
had an auto diaphragm.

 

[pphuang]

Thanks for the info and link! This site is great!!