There are many choices of the needle length, from 0.2mm-3.0mm. The needles ranging from 0.2-0.5mm is for home use and those over 0.5mm is for professional clinical or medical use. The needles ranging from 0.2mm to 0.5mm will reach epidermis layer, 0.5-1.0mm dermis layer and 1.0-3.0 will reach basal layer. Also, there are many options of needle quantity of the derma roller from 200pins to 1200pins, among which you can choose the most appropriate one. The needles are made of titanium or stainless steel and the handles of the derma rollers are made of high quality ABS plastic to assure a long-time service. There is derma roller kit to satisfy multiple needs, including 6 in1 derma roller and 3 in 1 derma roller. Among the kit, there are derma roller with different size and needle quantity. In all, there are many choices for everyone to find their own derma roller.