Filter funnels are filters that are used for solid-liquid separation by means of vacuum.– Filter funnels mate to the filtering flask via a conical rubber seal (GUKO) – From DURAN® glass with its good thermal shock and chemical resistance – Fired-on, highly durable white print – – Filter funnels are filters that are used for solid-liquid separation by means of vacuum.– Filter funnels mate to the filtering flask via a conical rubber seal (GUKO) – From DURAN® glass with its good thermal shock and chemical resistance – Fired-on, highly durable white print – –