Round-bottom flasks with four necks and [ST] outer joints

The outer joints are tooled with reinforcement rings for added strength and stability. Necks are vertical unless noted otherwise. Two of the side necks are in-line with the center neck. The third side neck is placed in front of the center neck and has a [ST] 10/30 outer joint that is suitable for thermometers. Heavy wall flasks feature walls that are approximately 30% heavier than standard flasks.