All the legal units of measurement shall be based on the International System of Units. However, the competent authority may designate the customary units other than the International System of Units as the legal units of measurement.
International System of Units are classified into two categories, the base units and the derived units.
The names, definitions and symbols of the base units, the derived units and the customary units as referred to in the preceding two Paragraphs shall be published per public notice by the competent authority.

The decimal multiples and submultiples of legal metrology units shall be expressed and written in the form of the numeral 10 and its positive or negative powers.
The names, definitions and symbols of the multiples and submultiples referred to in the preceding Paragraph shall be published per public notice by the competent authority.

A legal measuring instrument shall be marked or labeled with the legal units of measurement applicable to it, except for any of the following circumstances:
1. Where the legal measuring instrument is provided for export only;
2. Where the legal measuring instrument is provided as an accessory of an export product;
3. Where the legal measuring instrument is provided for use by manufacturing premises of which the products are for export purpose;
4. Where the legal measuring instrument is provided as an accessory of a machine or equipment being used by a manufacturing premise;
5. Where the legal measuring instrument is required by an academic research and experiment institution; or
6. Where the legal measuring instrument is required for use in national defense-related operations.

In case any measuring unit is used in trading or certification activities, the applicable legal units of measurement shall be used for such purpose. Regulations for promoting and assisting the use of the legal units of measurement shall be prescribed by the competent authority.