1. Translucent; 2. Temperature resistance range: -200deg.C~260deg.C; 3. Chemical inert, withstand virtually all chemical solvents; 4. Anti-pollution: low blank value of metal elements; 5. Non dissolution and precipitation: good vessel for storing standard substances, highly corrosive, ultrapure reagents; 6. Nozzle and cap in one shot: open autoclavable; 7. Can replace the volumetric flask to configure the standard solution: it can be controlled into a drop-by-drop state to add samples and water, and there is no residue in the return water nozzle.