Board Thread:Administrator Noticeboard/@comment-27.99.26.141-20130821054242/@comment-3075738-20130821222741

Go to your core files and delete the options.txt

Then restart Tekkit Classic.

You have your SensorNet hotkey on your Mouse 1 (Left Click).

Doing this resets your modified options to default options and changes your SensorNet hotkey to Semicolon.