These are extra thic dominoes model 540 by Crisloid Plastics/Catalin

The 4th picture shows a side by side comparison to a standard size Puremco domino (right).

The box is falling apart and was taped . Some words peek out for I’d edification and “540” is marked inside.

The 4 domino is dirty, may be stained.

We did the simichrome Bakelite test and the tip did turn out yellow after awhile.