I bought a 12in straight chamber PURE brand GonG bong. I accidentally broke of the slits at the perc end of the downstem. I have a few questions. 1. how do I correctly measure so I can get a new downstem that fits properlly? (lenght, diameter) 2. which company makes good quality glass for a reasoable price? 3. what difference does perc make when your rippin your bong? 4. have you ever heard of the above mentioned brand, PURE? and is it quality glass?