When selecting cleanroom coveralls, the fabric composition is critical. You must prioritize 98% Polyester and 2% Conductive Carbon Fiber (usually in a grid or stripe pattern). For high-standard environments, a 5mm x 5mm grid is superior to stripes as it provides more consistent static dissipation. Ensure the fabric is lint-free and high-density to prevent human skin particles from contaminating the cleanroom. Additionally, verify the surface resistance is between 10^6 to 10^9 ohms, which is the industry standard for effective ESD (Electrostatic Discharge) protection.