These are replacement inserts for a dough gun to extrude cheese straws. There are 3 different ones for different dough guns we have (different colors so they were easy to tell apart), each with different sizes and one physically different with notched edges rather than an edge rabbet. For each of these 3 there is a model with 1 star and with 2 stars. So A2 is model A with 2 stars for example.
I can't tell you by model which these go with. Dimensions of each model are in the PDF attached.