"Solvent 100 (C9)" typically refers to a type of solvent that is composed primarily of C9 hydrocarbons, which are part of the aromatic hydrocarbon group. These solvents are often used in industrial applications for their effective solvency properties. They may be used in formulations for paints, coatings, and cleaning products. The "100" often indicates the concentration or purity level of the solvent. If you need details about a specific application or safety considerations, let me know!