GoLab Laboratory Borosilicate Glass Conical Flask, Erlenmeyer flask, also known as a conical flask, is a type of laboratory flask which features a flat bottom, a conical body, and a cylindrical neck. 250ml Graduated Narrow Mouth Glass Erlenmeyer Flask Conical Flask 29/40 Ground Joints Description: Material: Borosilicate glass 3.3 Capacity:250ml Feature: 250ml graduated glass Erlenmeyer flask Made from borosilicate temperature tolerance, high strength and hardness High chemical properties, base resistance and acid resistance Narrow mouth design with 29/40 ground joints Large marked metric scale, easy to read Fit for lab chemistry experiment.