These are the tiles for the 15 + 4 puzzle, a hinged version of the classic 15 Puzzle, with an extra 4 tiles.
You will need to
purchase the frame for the puzzle SEPARATELY, at
https://shpws.me/SzQG
Carefully painting the numbers into the tiles (I used black acrylic paint) will make them much more visible. Alternatively, you can use a desktop printer to print these insets:
https://www.thingiverse.com/thing:5028866.