4" round 12 LED lights
I used 4" round 12 LEDlight from EBay $10.00 each,=
Pop the red lens off . (BTW) the more LED's in the light the better. remove all the stock light brackets from inside the trailer light, leave 5" of wire to connect to the new LED's. Dremal Grind about 1/4" of the fins in the housing to fit. test fit, I used silicon to hold in , let dry over nite. Don't forget the ground wire. Details about LED 4" Red Round STOP TURN TAIL Light w Grommet Pigtail for Truck Trailer See E bay.
Pic' may help=