Machinery and equipment which are used for fishing boats and exempt from business tax under Subparagraph 28 of Paragraph 1 of Article 8 of the Act shall be limited to fishing equipment, main engine, auxiliary engine, freezing equipment, power generator, communication equipment, fish searching equipment, navigation equipment and other machinery and equipment used for fishing boats conforming to any of the following conditions:
1. Machinery and equipment which are for exclusive use on fishing boats and conforming to the specifications specified by the central competent authority of agricultural affairs.
2. Machinery and equipment which are not for exclusive use on fishing boats, but are sold for use on fishing boats.
Any business entity selling the goods set forth in Subparagraph 2 of the preceding paragraph shall indicate on the uniform invoice the business license number of the fishing business of the purchaser or the reference number of the letter of the competent authority approving the building of the fishing boat involved and shall keep a photocopy of said approval letter on file for verification by the tax collection authority.