Description
This is the part that slides up and down the rails and has the arms connected to it at ball joints. If you are looking, instead, for the bearings that carry the whole assembly they are listed as FLSUN-V400-SLIDER-SET and are at this address – https://3dshop.uk/shop/flsun-v400-slider/
This listing is for one part so if you need to do all of your carriers you will need 3.
