Where can I find a cfl double socket?

I'm a noob to indoor growing, but it has def caught my interest. I saw a cfl post/grow, and the light sockets were in a y config., a "splitter" so to say. Where can I find one, or several of these?
I'm seeing in the indoor grows that all of the pro's stress it's very important in the flowering phase to make sure to close out any and all outside light leaks during the dark hrs. I understand why, and don't at all question their wisdom. I am curious, however, as to how the moonlight and other night time light sources impact my outside grow, particularly during the flowering phase?

they sell them in walmart/home depot in the states i believe. can only find them online in the uk.

The Y-splitters can be picked up in the electrical section of your local hardware store. The big box stores have them in among receptacles, switches, replacement sockets, etc.

As far as the moon light goes, it is a reflected light that the plant doesn't really "see". Light leaks in your grow are from lights they will "see" thus too much exposure to this light can confuse the plants cycle during flower, and some plants will hermie.

ebay has them really cheap. I have had less of those fuck up then the ones I bought from Walmart or Homedepot

home depot 2 bucks

Cool! Thanks for the input, and I'm sure I'll have a lot more questions as I stumble through the learning curve!