These are custom made OpenBuilds Tee Nuts. They were designed to slide into slots with less hassle than the standard rectangular tee nuts. They have angled corners to allow for a smooth transition.
OpenBuilds Tee Nuts fit V-Slot and most aluminum tee slot extrusion that has at least a 10mm wide tee nut slot.
Low Carbon Steel
M5 Thread Size
Note: Screws sold separately
QTY 1 = 10 Tee Nuts