A frient and I last night [9] were having a discussion about how much variation there is between the base of all bongs. We both agreed that pretty much all bongs have a very similar base dimension. Digressing into an incredibly interesting topic on base diameter to ease of tipping ratio, and why glass makers might choose a certain size, we figured it would be best to get some actual data. So we are curious, what is the diameter of your bong's base?