When sourcing inverter welding machines, you must prioritize IGBT (Insulated Gate Bipolar Transistor) technology over older MOSFET systems for better reliability and efficiency. Key specs include the Duty Cycle (aim for at least 60% at maximum amperage for industrial use), Input Voltage flexibility (110V/220V dual voltage sensing), and Amperage Range (e.g., 20-200A for versatile tasks). Ensure the unit features Hot Start, Arc Force, and Anti-Stick functions to improve weld quality and ease of use for operators.