This is a locking, sharp toothed lever cam operated bag clip.  Named in honor of “Kaiser”, the first US Military working dog to die in combat in Vietnam.

I printed mine with in PLA, with a raft, using 3 wall layers, 3 top layers, 3 bottom layers and 25% hex infill.  No supports needed as the model has built-in snap-off supports.  One in the front and one in the back.

There is an opening in the front that is visible after you remove the front support. The opening is for inserting a small flat bladed screwdriver to help pry the cam lever down.  The cam lever must be opened first,  and then the jaw can be opened.   

This is a one-print contraption with two internal cams that pivot on axles.  The air gaps are small, so it will help if your 3d printer is calibrated and prints to accurate dimensions.   It can be pretty stiff initially to crack loose the moving parts and get it working.  

Don't be afraid to break it when prying the cam lever down with a screwdriver. Worst case scenario, if you break it and gotta print another. No bid deal.  

Yo may also need to use the screwdriver the first time to open the jaws (after unlocking the cam lever).