Buyers must prioritize Pressure Rating (PSI/Bar) and Flow Rate (GPM/LPM) to ensure compatibility with their existing pumps. For industrial use, look for lances rated for at least 4,000 PSI. Material composition is equally vital; stainless steel pipes offer superior corrosion resistance compared to zinc-plated steel, while brass internal valves provide better heat dissipation and longevity. Additionally, verify the inlet/outlet thread types (e.g., 1/4" NPT, M22, or Quick Connect) to avoid assembly issues.