The file 'T-Nut For 25x25mm Extruded ALU Profile 3D Printer Model' is (stl) file type, size is 1.4KB.
This is a T-nut for 25x25 (or 1" x 1" for fellow Americas) extruded aluminum profile, which requires a M4 hex nut to be inserted (and is well hold in place by friction).
Fits well, might need to slightly sand edges.
ALU_2525_kamen.stl | 7.5KB |