Dermal rollers have a fixed needle depth which is not very conducive to treat an area like the face (which requires different depths because of the varying thickness of skin tissue and the area being treated). This is a huge drawback, one that the electric micro needling pen doesn’t have as the needle depth and penetration is easily adjustable on a micro needling pen. There is also a dramatic difference in the type of injury that these devices introduce into the skin. The micro needling pen needles penetrate the skin vertically whereas the derma rollers penetrate the skin at an angle causing tears in the skin and lead to more side effects and a longer recovery time.