You don't need a switch on a Featherweight just a removable link, LED's are used to indicate whether the robot has power or not, you wire them into your system so that when the robot is powered up the LED lights up and vice versa. Failsafe's are electronic cutouts that activate upon signal loss, I.e when the Transmitter loses signal with the receiver the failsafe will kick in and the robot will stop. They will either be built in to you receiver or speed controllers or you can buy external failsafes that you plug into your receiver and wire into your system.