What is the overvoltage protection on the Differential Voltage Probe and Current Probe?

In the DCP and DVP manuals, we specify that the maximum voltage on any input is +/-10V. This is our stated over voltage protection (our systems are designed for +6/-6V operation). These sensors are protected by a 6.2V zener diode and a 100 ohm current-limiting resistor in series. This works nicely at 10V. At higher voltages, there is a chance that you can damage the zener diode (but not the rest of the circuit). Applying higher voltages to these sensors can damage them.