HumiSeal® 1A33 is a single component, polyurethane conformal coating, suitable for general printed circuit board applications. HumiSeal® 1A33 contains no free isocyanates and fluorescence under UV light for inspection purposes. Cleanliness of the substrate is of extreme importance for the successful application of a conformal coating. Surfaces must be free of moisture, dirt, wax, grease, flux residues and all other contaminants. Contamination under the coating could cause problems that may lead to assembly failures.