The file 'T-nut M3 Drop-in Rotating (Prusa MK3 30×30 Alu Extrusion) 3D Printer Model' is (stl) file type, size is 12.3KB.
T-nut for 30x30 V-Slot aluminum extrusion like PRUSA MK3S (8 mm gap) compliant with M3 nut.
I used them to install the Rubber Feet Support for Prusa MK3 by Volan on the PRUSA MK3S