Your ordinary round-bottom flask has an outer joint, what we used to call female. These are inner (male) so will not fit into the usual place in a standard distillation setup. So what might they be for? They turn out to be useful when you want to minimize contamination by joint grease, since this geometry places the grease on the outside where even an aggressive solvent cannot get at it.

The nominal volume of the flask is 50 mL, the outer diameter is about 49 mm, and the overall length is about 75 mm.

The manufacturer is a bit ambiguous with red Ace Glass markings prominent on the top of the globe and the single flask neck, but white Kimble Kimax markings nearer the equator. (Multiple flasks have very similar labels and dimensions, which indicates they were made by machine in one or the other place.) Neither supply house seems to carry these items anymore. In any case, both are quality glass manufacturers.

When it comes to your chemistry, rely on quality name brands. Good glassware is ageless. Ships on the next business day by USPS (USA only). Shipping consolidation discount applied to the purchase of multiple units.

Item: 2xMSNRBF50