These rails are a result of a collaboration effort with CNA (BOM Sourcing Guide Recommended) and West3D. We went to them and asked them to think of our use case and design their rails specifically for high speed (and high vibration) 3D Printing. This resulted in us selecting a heavier than standard pre-load (a slight reduction in clearance between the rail and the carriage).

We then moved to improve the design aesthetic over what CNA typically ships. This gave us black carriage end caps and added our West3D logo on the carriage in a way that is tasteful and helps break up the traditional matte silver in the carriage block. We also made sure they provided us carriages with grease ports for your added convenience.

Lastly, we said why shouldn't these be stainless steel, I mean that's kind of our thing.

The result are these rails. We went through and tested 10 rails before listing these, all of our tests provided for a stiff (re: pre-load) but wonderfully smooth glide - especially compared to the standard 'kit' grade rails we tested.  

These rails are transitioning between variants - we now offer a Class H high precision rail. This class provides more consistent straightness (0.1mm over 1 meter length) and tighter tolerance of grooves in the rail (.002mm) with more uniformity over the rail.

 Note: if your rails come with grease on the rail, this is pre-applied mobilux ep2! This is not shipping grease!

Note - for a Voron V2 (and other)  users you require rails 50mm larger than your bed size, you will need multiple of these rails (please check your BOM if you're making build to confirm how many mms you need and the correct quantities).