Voltage regulator

There are a few out there that has a small what looks like a potentiometer on it. I know there are different voltages, Are they identified by plug color? I will try to find a pic of the adjustable ones. Thanks you guys are the best! Unchartered territory?

How about this thing.....


12 VOLT CHRYSLER ADJUSTABLE VOLTAGE REGULATOR
ITEM# C8313 (same as C8312 except adjustable)

For Chrysler External Regulated Round or Square Back alternators on Cars, Trucks, Industrial Applications with 2 Field connections.

Great for increasing voltage for brighter lighting. Just turn the dial and adjust as needed.


Features:

* 14.0 Voltage Setting, A-Circuit Neg. Grd. Solid State.
* Red Plug Connector.
* Adjustable Voltage up to 15.1V.

also this one
[ame="http://www.ebay.com/itm/Chrysler-Voltage-Regulator-/161134139669?pt=Motors_Car_Truck_Parts_Accessories&hash=item258457d915&vxp=mtr"]Chrysler Voltage Regulator | eBay[/ame]

I sent the seller a q asking him how it adjusts. When I get it I will post it.