4257 4257NA LED switchback bulbs turn signal lights replacement, dual color 6000K white/amber yellow upgrade OEM incandescent blinker lamps for 2019-2021 Ford F-150, F-250 super duty, F-350 super duty. front turn signal lights.
Light white for parking lights or daytime running lights. Light up amber-off-amber-off for turn signal lights instead of amber all the time to make more noticeable.
Extra load resistors maybe required to avoid the signal hyper flash or error code.
