Dark Horse Tattoo Pen This machine is compatible with all makes of cartridge needles on the market today, Hand assembled and made from space grade aluminium also CNC machined. Motor and Max RPM - 13V Japanese Kyosho Motor & 10,000RPM Suggested Voltage Setting - 5.5V to 6.5V Needle Stroke - 0 to 3.5mm adjustable stroke. Machine Connection - RCA Connection. Pen Power Cord - RCA Cord included. Weight and Length - 4.5oz and 4.6 inch Warranty - 6 month manufacturer warranty. (does not cover damage to motor from ink blow black)