Elplast offers audible resealable zippers for petfood packaging. When a resealable pack is opened, they create an audible opening noise at the correct frequency to attract pets, according to the company. This means dogs and cats can hear from some distance when it’s meal or treat time. The zippers are specially designed with extra cross-ribs to give off sound when opening and closing. This also reassures users that the pack is securely closed to preserve freshness. The double profile creates strength and means that pets are unable to open the pack independently.