Hummingbird rotary machine is made of aluminum which means better heat dissipation and lower operating temperature Adjustable Stroke: It is capable of hitting at any stroke length from 2.6 mm up to 5.5 mm for lining or shading. The Brass needle retainer keep's you'r needle perfectly stabilized and has no need for the rubber bands Only Need 5 Seconds to Turn it From a Liner to a Shader Without The Need of Touching The Power Supply Runs smoothly between 6-8 volts and has an RCA connection