SummaryThis is an M4 metric T Slot nut, that has to be used in slotted (6mm) Aluminum profiles. I use them for the frame of my new delta printer that is in construction The profile shown in photos is 20x40mmPrint SettingsRafts: Doesn't MatterSupports: YesNotes: printed with support in ABS I print them in multiple copy at one time (of course)Post-PrintingJust remove by hands printing support and slightly smooth surfaces with a file Press by hand an M4 nut in the receptacles. It will stay in position due to the low clearance between printed part and the nut