Designed for sensitive skin. While all uruoi has a focus on hydration as the core element of skincare, S-Series, specially designed for sensitive skin, takes it one step further. Formulated to be mildly acidic and gentle in its formula to soothe and calm sensitive skin, it helps to retain moisture, restore skin barrier, leaving skin soft and supple. Free of ethanol, fragrance, colorant, mineral oils, petroleum surfactant, and other harsh chemicals. S-series is not only a great choice for the sensitive skin but also great for someone who needs gentle skincare. To simplify the routine each product is marked with a number to match the sequence of use to U-Series.