Can filter chemicals that cannot be filtered by filter paper or diaphragm; can be used with filter flask, filter adapter cones and others; ideal for chemical analysis, petroleum industry, pharmaceutical industry and so on. 24/40 Joint; glass Filter Funnels; made of borosilicate glass. G3 15-40 μm Nominal Max. pore size; compatible with Qualitative/Quantitive Filter Paper Circles in 94 mm diameter. Heavy duty design, premium quality, low expansion coefficient, heat and resuable. Borosilicate glass; heavy duty design; reusable and high quality.