Flasks, Round Bottom, Three Necks Parallel, DIN & USP (New)
Manufactured from 33 expansion, borosilicate glass conforming to USP
Type I and ASTM E438, Type I, Class A requirements
Specification
Universal Scientific Glassco: Flasks, Round Bottom, 3 Necks, Parallel DIN,ISO .You seem to be talking about a particular kind of glassware used in laboratories, which is round.