This is a vertical X axis that conforms to the reprap vertical x axis standard. It uses a particular 10mm Acme leadscrew (Discontinued: a comparable can be found here) but an adapter is available that hold an m8 nut for standard studding-driven mendels. I'm not certain that the PrismX or OB1 prism conforms to the standard spacing (I'm not even sure the Sell's Mendel does; i recall that the spacing was a bit arbitrary), so double check your printer before printing out the pieces! It includes a Greg's/Wade's compatible carriage, but an integrated carraige/extruder is to follow. This is a refinement on a design i worked on a couple years ago. Hope you like the Art Deco inspired design.If using standard M8 Studding- you will need to print: 2 Motor mounts 7 lm8uu holders 1 Z Carriage x- 1 Z Carriage x+ 1 X Carriage You might also need to print: -the Z leadscrew support and if using with a Prism printer -a belt-compatible pully if using a belt-driven Z -the z leadscrew top bearing restraint (hold bearing on end of studding/leadscrew, but allows some play) To attach the belt to the carriage, I put m4 screws through some of the hex-pattern holes on the carriage. I used some m4 fender washers of 20mm diameter, but you can easily design and print something to secure it if you don't have similar washers. there's no need to make the belt tight when attaching to the carriage because, once the bent is secured to the carriage, you can move the x motor to tighten the belt.