Mobius Stereo Matrix Fixed Stem Bubbler. Mobius Glassworks is now making their stereo matrix percs inside of their all new style bubbler. They have fixed stems and are diffused by dual percs. In this one's case, by dual Matrix percs. The pipes are built on 65mm tubing and have 20mm bent necks with a 32mm mouthpiece. It is 14" tall and sits on top of 5" diameter foot which is 5mm thick. The stem is topped with an 18mm male joint and an 18mm female push bowl. Available for purchase in-store or buy Mobius Glass online.