| 摘要 |
Device for giving warning, by an audio signal, of the absence of a card in a card holder. The invention relates to a device making it impossible to forget a card during its use. It consists of a card holder in which there is an alarm, contacts serving as switches linked to the alarm. When the user withdraws a card and closes the card holder, with the contacts touching, the alarm is triggered. The device according to the invention is particularly intended for all magnetic or other cards of credit card form.
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