They are puzzle-shaped pewter tokens, engraved on the one side with the words “I AM” and on the other with the affirmation of your choice. Like “BLESSED”, “DEVOTED”, “LOVED”.
They’re available as bracelets, necklaces or just loose (from The Good Cheer Company!) and would make good bridesmaid gifts or favours. There’s even one that on one side says “WITHOUT ME” and on the other “THE PUZZLE IS INCOMPLETE” that you could give to the groom as a reminder!