These fender turn signals (also known as "Side Repeaters") are found on all European and Japanese 300zx models. When installed they add both an additional level of safety as well as JDM style.
OEM US fenders must be cut to accomodate these Turn Signals. Z1 stocks used JDM fenders with the mounting slots already cut out.
To wire, simply attach the fender signal's Ground and Turn Signal wire to the appropriate wires on the front turn signal in the front bumper.