Are you talking about a bottle->bong conversion kit?

I think he's talking about a replacement bottle cap that has a bowl, downpipe, and mouthpiece/tube attached. The idea is that you can then instantly convert any bottle to a handy bong. All you need is the kit and a bottle, and Voila! You have yourself a bong. Quite brilliant, actually.

If that's not what you're talking about, I apologise for rambling.