Tektronix P5120 200 MHz, Passive High Voltage Probe

The Tektronix P5120 probe is designed to isolate measurements from earth ground and also to isolate the common voltage between scope channels. The Tektronix probe P5120 provides isolated channel performance up to 1,000 VRMS CAT II when used with the Tektronix TPS2000 Series oscilloscopes.
 

With the Tektronix high voltage probe P5120 and the Tektronix TPS2000 Series handheld digital storage oscilloscopes you have not only the isolation for the measurement from earth ground, you also have full isolation between the two channels.

Note: The Tektronix P5120 high voltage probe is not intended for making floating measurements on scopes that lack the appropriate safety features needed for making floating measurements.