GrabCAD
This is HIWIN HGR15R rail and HGH15CAZAC sliding block for linear guideway. Rail is configurable in term of length and first hole distance. Grease nipple is not HIWIN type. Original is K model ball type DIN 3402, grease nipple with M4x0.7. This grease nipple was originally M8x1.0 DIN 71412 90 deg standard nipple. After little work on lathe it become like this.
Direct link to the original creator's page
This model is published by its creator on GrabCAD. STLFinder only indexes it: the "View on GrabCAD" button above opens the original page, where the creator shares the PARASOLID, RENDERING, SOLIDWORKS, STEP / IGES files under their own license.
This model is compatible with most FDM 3D printers (Creality Ender 3, Prusa MK3S+, Bambu Lab, etc.) and resin printers (Elegoo, Anycubic). Check the original page for recommended print settings and materials.
Yes, the creator shares it at no cost on GrabCAD. Some creators accept tips or donations.
Check the license (see original page) on the original GrabCAD page. Most STL files can be modified using free software like Blender, TinkerCAD, or Meshmixer.