Khóa cài ba lô chắc chắn

The buckle of my backpack broke, so I created one that fits.
I continued on the existing design by 3DMakerNoob. 

- Improved the sliding-mechanism. (Both for the buckle as the buckle-holder)
- Stronger clips → less flex so less plastic deformation.
- I also uploaded a version with an antislip attachment, so that the buckle stays better in place.

I printed it on a Bambulab p1p printer in black ABS. Should also work fine with other materials and printers.