7mm 4x6 Arm Tree Perc Bong7mm 4x6 Arm Tree Perc Bong by Grace Glass We're huge fans of Grace Glass here at EDIT. Their classy styling and quality of of craftsmanship make their glassware highly desirable. This 4x6 arm tree perc bong is hand made from 7mm thick, top quality borosilicate glass and stands an imposing 55cm tall. The beaker base, mouthpiece and percolator are all tinted with more swirls of colour inside the tube. The scientific design filters your smoke removing