For pretty much any application, single high/low, individual high and low, 1 bulb, 2 bulbs, 4 bulbs. This is the "old" style that involves cutting and taping into wire harness.
Installation is pretty simple:
Cut low beam wire, use wire taps to connect the cut wire ends to two wires on the modulator.
Cut high beam wire, use wire taps to connect the cut wire ends to two wires on the modulator.
Mount the photocell.
Tap into horn wire (optional).
Connect ground wire from modulator to any ground point.
I used this for several years on my C10, never a problem and definitely improves visibility.
$25 shipped
Wayne