yah the socket you insert in the cap does matter. It doesnt have to be big at all. Just wide enough so you can easily light it up. So a small wide one is good enough. I used one like the one in youtube. Check it out in youtube.com and as search insert " sobe waterfall" and you'll see it in more detail. Strongly recomend this i wish i would of done it earlier. Spring break would of been even more of a blur...