A derma roller is a skin needling device with many small needles. Derma rollers come in needle lengths between 0.13 and 3 mm. The needle diameter (thickness) is approximately 0.25 mm at their base. Our rollers have a .25mm length. Just by gently rolling your Derma roller over the skin a few times a week, your skin will begin to look and feel better and cleaner. Other Derma roller Benefits: Using a Dermaroller has a second very important function. By removing dead skin cells on the skins surface, rollers will boost the absorption of products applied to the skin by a factor of thousands! This means that if you are using a skin cream, hair lotion or any other topical; you will see massive improvements in their results. It will also slash the cost of using these products as using a Derma roller means you don’t have to use as much to get the same effect.