Erlenmeyer flasks are typically made of two main materials:

· Glass: Borosilicate glass is a popular choice due to its heat resistance, chemical resistance, and transparency. It is often used for applications that require precise measurements and high temperatures.

· Plastic: Polypropylene (PP) and polycarbonate (PC) are common plastic materials used for Erlenmeyer flasks. They are lightweight, durable, and often autoclavable, making them suitable for applications that do not require the transparency of glass.

The choice of material depends on the specific application and the properties required for the flask. For example, if high temperature resistance is needed, a glass flask would be more appropriate. If autoclaving is required, a plastic flask might be preferred.