A derma roller is a medical grade micro-needling device which is used for skin regeneration. It is made of a heavy-duty plastic roller head which has about thousands of tiny needles on its surface. These needles are either made of stainless steel or titanium. Different rollers have a different number of needles. Ideally, there would be about 90 to 450 needles and the size of the needles would be between 0.25mm to 3mm.