DankTips NEW 5 Ultra Premium Flat-Mouth Quartz Glass Filter Tips by Made by DankTip's, the #1 rated glass filter manufacturer on Amazon. Undisputed highest quality glass of any glass filter tip manufacturer! We use Quartz glass that has a 99.5% SiO2 purity range, while nearly all other manufacturers use cheaper borosilicate usually in the 80% purity range. We've developed proprietary techniques to work with this glass which allows us to provide our product cheaper than our competitors who are using lower quality, cheaper glass. Read the product description for the advantages of quartz over borosilicate. Enjoy better taste, along with smoother puffs versus paper filters. No more nasty saliva and resin soaked ends that come along with cardboard or paper filters. Not only is this gross, but it also restricts airflow! Our extremely durable filter tips are completely reusable and designed to be far easier to clean vs. the glass tips made by our competitors.