Cellphone Charms That Lights Up Where Do You Buy Korean Cellphone Charms For Couples?

Where do you buy korean cellphone charms for couples? - cellphone charms that lights up

Hey, where can I buy Korean mobile charm for couples? I remember I had a role in a music video where a man gives a girl a phone charm that comes on. and lights when they are together. if they are close to each other turns on the charm.
Does anyone know where they sell?