The HAIRLICIOUSLY 192 Needle Derma Roller 1.5mm is one of the best selling items used to stimulate hair growth. The 1.5mm Derma Roller is equipped with 192 medical grade REAL stainless steel needles that will penetrate the scalp to induce collagen production, increase blood flow, and release hair growth stem cells. BEWARE of other Derma Rollers which do not utilize real needles.