Biscuit Tea Infuser
Tea infusers are considered as complementary goods for tea. Complementary goods is a term economist and investors use on a product which adds value to another.
But not this tea infuser. Considering its price ($15) compared to a standard tea infuser ($6.99) and considering its appearance that serves no purpose other than to attract attention, this tea infuser is considered as a luxury good. A luxury good is a type of product that is expensive and commonly purchased by wealthy people to show off.