TM 1-1500-204-23-6 Table 5-1.  Identification of Plastic Materials - CONT Commercial Current designation specification Form Grade and Intended use Cellulose L-P-504 Sheets Type I-General Purpose Acetate Type Il - Superior Mechanical Plastic Sheets and Optical Type III-Superior Glazing Plastic Sheet, MIL-P-6264 Sheets The Plastic Film Covered by Vinyl-Copolymer, This Specification is Intended for Thin Use as a Backing for Sound Proofing Blankets on Aircraft. Plastic, Sheet MIL-P-5425 Sheets Finish A-For Transparent Areas Acrylic, Heat- on Aircraft Where a Material With Resistant Good Optical, Formability, Outdoor Weathering, and Heat-Resistance Properties is Required. Finish B-For Use in Reinforcing Ribs, Moldings, etc.  of Trans- parent Acrylic Assemblies. Plastic Sheet, MIL-P-8184 Sheets Finish A-Material for Transparent Acrylic, Modified Areas on Aircraft, Has Good Optical, Formability, Crazing Resistance, Outdoor Weathering and Heat Resistance Properties. Finish B-Material is Intended for Use in Reinforcing Ribs, Molding, etc.  of Transparent Acrylic Assemblies. Molding Plastic, L-P-397 Cellulose Acetate Plastic Rods and MIL-P-79 R-Rods Type PBE-General Purpose Material Tubes, Molded Fairly Good Mechanical and Elec- Thermosetting, TR- trical Properties.  Under Adverse Laminated Tubes Conditions of Temperature and Rolled Humidity PBE Possess High TM- Dielectric Strength and Relatively Tubes Low Dielectric Losses. Molded Type PBG-General Purpose Material Combining Fairly Good Mechanical and Electrical Properties. Type PMB-Use for Structural and Electrical Applications Where No Moisture is Present, Applications Where Electrical Properties Are Subordinate to the Required Mechanical Properties 5-4