Which product type is noted for having no pH?

Nail polishes are noted for having no pH because they are formulations that contain solvents, resins, pigments, and other ingredients designed for coating the nails. Since they are not water-based like shampoos, conditioners, or hair gels, they do not have a measurable pH. Products with a pH, such as shampoos and conditioners, typically include water as the main solvent, which contributes to their acidic or alkaline properties. In contrast, the formulation of nail polish does not involve the same chemical properties that would necessitate a pH level, making it unique among the options provided.