Regulations for Exemption of Commodity Tax on Goods for Military Use Article 13

The Military Goods Approval issued by the Ministry of National Defense or its authorized unit for the purchase of taxable goods shall be valid for six months. The Approval shall be valid for one year if the taxable goods are purchased for the replacement of major machine components.
中文原文 軍用貨品貨物稅免稅辦法第13條
國防部或其授權單位核發之軍用貨品核定單,採購應稅貨品有效期間為六個月,但採購之應稅貨品係改就主要機件課稅者,有效期間為一年。

English translation for reference only; the Chinese text prevails. Not legal advice.