Select from three sensitive options to achieve precise high impedance and low current measurements.5½-digit 6514 and 6517B models offer 1fA sensitivity, voltage measurement with input impedance >200TΩ, and charge measurement down to 10fC. The 6½-digit 6430 model ultra-fA remote SourceMeter SMU instrument can measure current with a sensitivity of 1aA. It features low noise and minimal offset, making it highly suitable for research on single-electron devices, high-resistance nanowires and nanotubes, polymers, and electrochemical applications.