Finish A.- on aircraft where a material with good optical, formability, and outdoor weathering properties is required.

Finish B.- Finish A material is primarily intended for transparent areas Finish B material is intended primarily for use in reinforcing ribs, molds, etc, of transparent acrylic assemblies.

In case material conforming to this specification is used for specialized optical purposes, more rigid optical requirements may be specified in the detail product specification.  In this event, the requirements of the detail specification shall prevail,

Reference to this specification on drawings or in product specification may be made in order to specify the flat material to be used in the fabrication of a part. It must be clearly understood that the requirements apply to the flat material prior to forming or fabrication and not necessarily to the material in its final form.