I desinged this one to be printed with two or three walls and no infill with tpu to prevent the key of my Door Lock to fall out when I open the Door too fast. It is designed for old warded Locks or in Germany they are called Buntbartschloss for so called Bartschlüssel and it is a very snug fit so you have to squeeze the Block togehter to get it in and out.
The author marked this model as their own original creation.