We're currently using Igus pillow blocks on our Mendelmax builds. So far testing is showing these bushings are working very well. They are smoother and more quiet than any other bushings we've tested.These go together just like all of our other clamp style x ends and carriage. The only change is the bushing mount holes are wider to accommodate for the wider Igus bushings.These Igus bushings can be sourced from our LulzBot.com store and Igus.