Hello Kouta,
Thank you for your e-mail.
Your package was flagged because it contains Night Vision which is controlled for Export from the U.S. We were able to confirm that the ECCN (Export Control Classification Number) was EAR99 which is approved for shipment. Your package has been released and is now available for review or shipment at your convenience.
Please let me know if I can be of any further assistance.
Best Regards,
意訳です。