Selecting the correct Denier (D) and Filament (F) count is critical. For lightweight apparel like summer shirts, 50D to 75D is standard, while heavier fabrics like upholstery or sportswear require 150D to 300D. A higher filament count (e.g., 75D/72F vs 75D/36F) results in a softer hand-feel and better moisture absorption. Additionally, specify the luster required: Semi-Dull (SD) is most common for general apparel, Bright (BR) for high-sheen decorative fabrics, and Full-Dull (FD) for matte finishes with UV protection.