Improve the thin hair look instantly with the use of Toppik Light Brown Hair Building Fibers. The bottle is filled with thousands of micro hair fibers that adhere to the hair, changing their thinner appearance to thicker one. The addition of light brown hair building fibers not only gives a fuller look but also adds a soft dimension to hair, making them appear rich and natural. The fibers turn invisible to eyes once settled on hair and are resistant to water, sweat and wind.