Fudau is a professional manufacturer of Erlenmeyer flasks, and here is the product information for our 1000ml Erlenmeyer flask: Height: 216.8mm Neck diameter: 39mm Bottom diameter: 127mm Working Volume: 500ml Material: Polycarbonate (PC) Cap Options: You can choose between a PC flask with a vent cap or a PC flask with a seal cap. Manufacturing Standard: Our products are produced in accordance with the c-GMP (current Good Manufacturing Practices) standard to ensure quality and safety. Cap Material: The bottle cap is made of high-strength HDPE (High-Density Polyethylene) material. Cap Design: The cap is designed with a PTFE (Polytetrafluoroethylene) hydrophobic and breathable membrane. This design ensures that, even after coming into contact with liquids, it won't compromise the sealing and ventilation properties of the breathable membrane. Flask Material: Our Erlenmeyer flasks are made from high-quality polystyrene (PS) raw material, which conforms to USP VI medical grade standards, ensuring the flask's suitability for a wide range of applications.