The Erlenmeyer flasks that Pacific Northwest Mycology offers are Laboratory grade, made with durable borosilicate 3.3 glass and feature a heavy-duty rim with wide-mouth opening. There are very few applications these flasks cannot handle.
An Erlenmeyer flask allows for more consistent spinning of a liquid culture (as compared to a mason jar) due to it's flat base. Erlenmeyer flasks can also be used for many other mushroom growing laboratory tasks.