Everything seems fine. I didn't measure to make sure it was exactly 400mm. I use it to upgrade the dual Z axis on my Ender 5 and it fits the bill. It's a little cheaper than Misumi but still seems to be of good quality. I was a little annoyed that they were sent separately - I had to use huge boxes for two rods but I guess you can tell they were well packaged.
Goodyear Ultra Grip Ice SUV 235/65 R17 108T winter
35 Review
Iverntech MGN12 700Mm Linear Rail Guide With MGN12H Stainless Steel Carriage Block For 3D Printer And CNC Parts
11 Review
Iverntech MGN12 700Mm Linear Rail Guide With MGN12H Stainless Steel Black Carriage Block For 3D Printer And CNC Parts
9 Review
Iverntech MGN12 400Mm Linear Rail Guide Upgrade For Ender 3, Corexy, Tronxy, Delta Kossel 3D Printers And CNC Machines With Stainless Steel Carriage Block
12 Review