Round bottom, three neck flask. Side necks are angled. Available in standard wall for more rapid heating or heavy duty for mechanical shock resistance. Microscale flasks, codes -34 & -36, feature 14/10, 20-400 externally threaded cap-seal joints supplied with 14.7-15mm holed caps, PTFE faced septa for sampling and FETFE o-rings for creating a compression seal with a 14/10 male joint (place the o-ring above the male joint and the cap completes the seal).