This is a support bracket to stabilise the frame of the D810 Delta 3D Printer and reduce wobble of the Frame when its moving quite fast.
Each piece mounts to the m5 Screw that holds the acrylic in place and with a m3 screw and nut to the 2020 aluminium extrusion.
You need to print the part six times, half of that must be mirrored.
Print the part with the flat site on the printbed.
If you use a higher infill, it could be even stronger.
From my testing, 30% is more than strong enough.