Support circulation & stimulate the scalp This root-boosting derma roller uses 540 premium strength stainless steel needles to deliver stimulation to the scalp. Using the derma roller creates micro-abrasions in the skin. This micro-needling enhances the absorption of ingredients and invigorates the hair and scalp. Use in combination with the supercharge range of Growth Bomb treatment products to unlock the potential of your scalp care routine.