
I have used these sliding blocks on my 3D printer and after repeated use I noticed that some of the C-rings or snap rings, whatever you want to call them, held enough stock used to scratch the poles they slide on. I can't say for sure if I lined them up correctly, but I still think the designer should have considered the damage they can cause at slightly different angles.

Iverntech MGN12 700Mm Linear Rail Guide With MGN12H Stainless Steel Black Carriage Block For 3D Printer And CNC Parts
9 Review

Iverntech 400Mm MGN12 Linear Rail Guide With 2 Black Stainless Steel MGN12H Carriage Blocks For CNC Parts And 3D Printer Upgrades
8 Review

Iverntech MGN12 700Mm Linear Rail Guide With MGN12H Stainless Steel Carriage Block For 3D Printer And CNC Parts
11 Review

Powerful And Waterproof Electric Micro Linear Actuator 12V With Mini Size And Mounting Brackets For Various Applications
11 Review