Putting your business logo there makes this game a business card as well as a product. A silkscreen or rubber stamp would work well. A steel flat washer from the hardware store makes a good ring. Heavy fishing line, plumbers line, etc. makes a good cord. Painting fishing line makes it smoother and prevents fraying.
Bright red is a good attention-grabbing color to paint the game.
Glue the knots so that no one will untie them.