The EGT probe is a sensor that allows users to monitor critical Exhaust Gas Temperatures to ensure added power is not creating excessive heat which, in turn, can cause engine damage. With the EAS system a user can connect multiple EGT sensors to monitor temperatures in different locations and compare readings to be even more precise. This kit is a basic EGT probe kit for CTS3 owners already running some EAS accessories. This does NOT include the EAS start kit that would be needed and assumes you already have it. If you're looking to add an EGT sensor to your CTS3 system and don't have any other EAS accessories, you'll want to order part number 98620.