The most common size used to make starters using White Labs brand yeast. Same as our Y300 Starter Kit, but with a 1000ml Erlenmeyer flask instead of the 500ml.,,(We do not recommend the use of an electric element with these flasks. If this cannot be avoided, we recommend using a larger pot as a hot water bath on the stove.),,In the lab world, these flasks are known as "Student Grade". A great flask for making yeast starters!(Student grade is not the highest grade flasks and will have minor defects)