Made out of quality borosilicate clear glass, high-temperature resistance, healthy than original painting glass. 3mm thick wall thickness, durable for heavy use, not broken by accidental knock-off, and the inner diameter is approx. 38.5mm, perfectly designed to fit the proxy device. Sleek & convenient shape, easy to grip, and portable to go anywhere. There are assorted colors available for your custom- Clear, Blue, Green, Amber, and Teal. Original manufacturer, we produce, bulk sale, and custom all kinds of proxy accessories - pipes, adapters, bongs, dab rigs, recyclers....syi