This is designed to create an secure tube system using a Raynox DCR-150 or Raynox DCR-250 lens as tube lens. It includes the following:
 
1x MJKZZ VLE variable extension
1x M42-to-M43 adapter ring (M42x1 M43x0.75)
1x M42 to camera mount of choice (such as Canon EF or Nikon AI)
1x M49 to a set of RMS, M25x0.75, and M26x0.706 adapters
3x Simple 3 segment extension tubes
3x Tube lens clamps with screws
1x 160mm long double slot Arca Swiss compatible plate.
 
The benefit of using Nikon extension tubes is that it has large enough inner diameter and grooved inside to prevent internal reflection.
 
Note pictures shown above include some other items for demonstration purpose only.