A nice little cap for the Z- axis of the MPCNC. This fits 23.5mm EMT, but if you scale it up a bit, it should fit the MPCNC-IE version tubing.
If you don't know what an MPCNC is and just want a cap for any old tubing, just scale this thingy to what you got. ;)
I found that I can leave the little bed squish on there for a tight fit.