This is a two level belt clamp for a CoreXY 3D printer I am designing. It is fully 3D printable without support material, is self-locking, and will not slip not matter how much tension you put on the belts. No unsightly zip-ties are needed. I am using F608ZZ bearings on the X axis in my design, 22 mm OD. This clamp is 22 mm wide so the belts always remain parallel to the X axis. I designed it for 9 mm wide belts, but it is easily modifiable for 6 mm belts. I use two #6 screws to mount it on the extruder carriage. The screws could be used to adjust belt tension, but I prefer to adjust belt tension individually, at the motor mounts.