In the spirit of complete transparency.
I bought this Z axis a couple of years ago and It has worked beautifully for me.
However, recently I have been having a problem with it not holding the correct depth during a carve. ( it would slowly drift downward)
I thought there was something wrong with it, so I took it apart and replaced the bearings.
Put everything back together, and my problem didn’t go away.
Also noticed that I had (what I consider) excess backlash in the delrin nut.
SO, I ordered a new Z axis.
During the time it was in transit, I remembered that I played with the Z max speed and also the acceleration rate.
When I reset GRBL to the original settings, the problem went away.
Lesson learned, don’t ask the machine to do more than it is capable of.
But alas, I still had a delrin nut that was worn out.
So my new Z slide came, I installed it and all is well.
This unit will come exactly as pictured.
You will need to use your own belt pulley, bearing, delrin nut, and lead screw.
All this being said, I think the Z slide is still worth $50.00 plus shipping.