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Time for Change toothbrush uses a special ink to remind people to change their toothbrushes regularly. This kind of ink will fade gradually with the passage of time and disappear entirely at last. When a toothbrush is needed to replace, the text on the toothbrush handle will become “change”, people know it’s time to change their toothbrush apparently.
Zhejiang University
Ningbo, China
Yu Liang,
Zhejiang University