These 250mL PYREX® long neck shaker culture flasks are basically Erlenmeyer flasks to which a long straight, rimless neck of heavy tubing has been added. The longer necks reduce the amount of splashed solution reaching the closure. They are ideal for shaker cultures. Their uniform wall thickness provides the proper balance between mechanical strength and thermal shock resistance. For convenience, these flasks include a marking spot. The approximate neck O.D. is 38mm. (For closures see Item No. COR-26796-38 and COR-26797-38) 12/Case. Corning #: 4442-250. Capitol #: COR-4442-250.