Help promote hair fullness, thickness, and overall scalp help with this scalp derma roller from Act + Acre. Using 540 high-strength medical grade stainless steel needles, the roller creates micro-channels on the scalp to stimulate blood flow to the hair follicle and release growth factors to stimulate hair growth while increasing topical product absorption. * 0.25 mm-sized needles * Ergonomic design * Carrying case included * Safe for all scalp types and hair textures **How To Use:** On clean damp or dry hair — using gentle pressure, roll horizontally and vertically across the scalp (1-2 x per section)