Cold Food Smart-tag ( 5°C) is a temperature indicator that shows how long your product has been above refrigerated temperature (5°C /42°F). It’s UK technology, manufacturing in Israel and partly assembly in H.K. It's applicable to cake pacakging, Sushi packaging, or ice-moon cake. 

It can be stored at room-temperature then attach to a product or package when needed. It is single use and indication id irreversible. It is splashproof and there is an expiry date on each pack shipped.