English to Italian Marketing Materials (Plastics, Ceramics, etc.)

Sto traducendo la descrizione di un tappo e non riesco a trovare l'equivalente in italiano di 'Band's bridges'...

"when the flip-top is pushed open for the first time the band’s bridges break automatically, the lower section then drops to the base of the spout and is retained there as permanent evidence of opening."

Cosa potrebbe essere?

Grazie!