If you look at the product page on Rivco's wesite, you can see that the bulb actually has a small fan at it's base. The bulb and fan unit are all one piece. The factory bulb adapter is re-used basically as a connector.
You can see in the instructions that the connector at Picture 3B goes into the OEM adapter which then plugs into the bike's power. http://rivcoproducts.com/instruction...truct_3-16.pdf
The wire retainer is removed in the install and replaced by a spring clip that holds the unit in place. You can see it in 4A of the instructions. I will say that I did bend that spring clip a bit more to create a little more tension. I'm not sure I had to but it didn't hurt anything.
You can also see that the rubber boot is use to seal this unit into the head light fixture. See 3A