FLSUN Cube Frame Stiffener

I wanted to stiffen up the frame a bit so i quickly slapped together this frame-stiffener in Fusion360

The stiffener can be mounted using 7 M4 bolts in every corner of your frame.

I printed this solid but not sure if that;s needed, check for yourself :)

Oh, the size of the part is 12cm x 12cm.