Great for any 3D projects requiring a belt.  Designed for 3D printings these buckles require no support  and include four sizes:  ½ inch, 5/8 inch, ¾ inch and one inch.  The female end has extra loops for a more permanent lock on the belt material whereas the male end is quickly adjustable. Works well with nylon or elastic webbing. 

I iterated on the design quite a few times and this is version 12. If you see any improvements that could be made your comments are appreciated. The files are not scaled versions of each other as belt thicknesses have been accounted for.

Each pair can be printed as laid out in the stl file with the female piece printing on edge.  Good bed adhesion is needed or use a small raft in your software settings.