When evaluating conductive gel, prioritize viscosity levels to ensure the medium stays in place during procedures without being too runny. Look for high electrical conductivity (low impedance) to ensure clear signal transmission for ECG, EEG, or TENS applications. Additionally, the gel must be water-soluble, hypoallergenic, and bacteriostatic to prevent skin irritation and cross-contamination. Ensure the formula is salt-free and formaldehyde-free to protect sensitive medical equipment probes from corrosion.