This is designed to create an extension for tube lens when using an infinite microscope objectives. For example, using a Raynox DCR-150 lens as tube lens. It includes the following:
 
1x MJKZZ VLE variable extension
1x M42-to-M43 adapter ring
1x M42 to camera mount of choice (such as Canon EF or Nikon AI)
1x M49 to RMS adapter (other thread size are available soon)
3x Simple 3 segment extension tubes
 
Note pictures shown above include some other items for demonstration purpose only.