festival glass, or soft glass as it is sometimes known is a lower quality type of glass, as compared to the borosilicate glass that name brand bongs like roor, toro, and gspot are made out of. I wouldnt reccomend it except for small inexpensive bongs, as it is quite heavy, not as strong, and the glass has inherant stress in it from not being tempered in a kiln after the blowing proscess.