✅Precise Measurement: This 100ml Volumetric Flask is made from Class 'A' borosilicate glass, calibrated to contain for accurate measurements in laboratory applications. ✅Polyethylene Stopper: Fitted with a chemical-resistant polyethylene stopper, ensuring secure and reliable closure during experiments. ✅Blue Graduation: The flask features blue graduation markings, providing clear and easy-to-read measurement indicators, meeting ISO 1042 standard. ✅Socket Size 14/23: Designed with a socket size of NS 14/23, this volumetric flask is suitable for various laboratory setups and applications. ✅High Heat Tolerance: Crafted from borosilicate glass, the flask has excellent heat tolerance with 20°C. ✅If you need custom order with different sizes/design please contact KingMariot Storefront on Amazon. ✅Safely Packaged to avoid being damaged during transportation. If received broken please provide the image to receive instant refund.