The Etude House My Lash Serum Promotes Strong And Healthy Lashes By Preventing Lashes From Not Falling From The Roots. This Clear, Transparent Formula Contains Biotin, An Essential Component That Supports Hair Health, Which Is Also Used In Shampoo And Supplements To Strengthen Hair. With A Mascara Brush As An Applicator, This Screw Brush Type Delivers The Serum To The Lashes And Roots Thoroughly.