Light, small, portable, compact design. High speed & High efficiency and low cost. Simple operation, easily remove broken tap. Full Power Source Choices: 100V/110V/120V/200V/220V/230V/240V, 1 PHASE, 50HZ/60HZ. Dielectric: Using ordinary tap water as machining dieletric liquid. Electrode: Using any brass bar as electrode Flexibility: Machining easily even on a large work piece. No damage: Remove taps easily without damage the threads. Complete functions: Auto feed, depth setting (stop at a specific depth), selectable arcing timer, auto retrace, work head swivel alarm message: depth arrival, arcing, over- temp.