Huayu Double axis guideway SGB
https://www.hyballscrew.com/product/double-shaft-guide-rail/double-axis-guideway-sgb.html
Double guide rails use double-row ball bearings as rolling elements. Double-row ball bearings have the great advantage of bearing axial and radial loads when rotating at high speeds. For multi-axial loads, the double-row ball bearing has two points of contact with the guide rail shaft, and the outer ring is precision ground after grooving heat treatment. Also, it has grease in it. Therefore, it does not require additional oil replenishment until the end of its useful life.