Yes, you have to send the articles in one of the registered letter envelopes sold by the post office.

是的，你必须用邮局出售的一个挂号信信封寄这些物品。

Compensation will not be paid for the following articles, such as bank notes, currency notes, trading stamps, coupons and some valuable things unless they are enclosed in one of the registered letter envelopes sold by the post office.

下列物品，如纸币、纸币、邮票、优惠券及一些贵重物品，除非装在邮局出售的挂号信信封内，否则不予赔偿。