The input impedences of our voltage probes are all listed on in the LabPro Technical Reference Manual. For a normal VP-BTA voltage probe used with LabPro:

Input impedance: +/-10V input 1MΩ

Note that if one was to use a VP-DIN on a LabPro (via adapter) the input impendance would be:

Input impedance: 0 –5V input >10MΩ

For the input impedance of the Differential Voltage Probe, see Differential Voltage Probe Troubleshooting and FAQs.