050-0493-00
Tektronix part number 050-0493-00 is a modification kit for the P6038 sampling probe. The modification replaces the sampling diodes that are used in the probe. The old diodes are GaAs, and have a blue dot on them, and are part number 152-144 (or 152-0144-00 in the new part numbering system). The new diodes are silicon, have a purple dot on them, and are part number 152-0441-00.