Microbiology is an important field of biology and medicine and deals with microorganisms (bacteria, fungi, protozoa or viruses) and their habitats and conditions. For this purpose, it is essential to produce pure culture media on which the corresponding microorganisms can grow. Irradiation of the media with IR or UV light can accelerate the growth of the cultures. Culture flasks have large bottom surfaces that are as flat as possible so that the layer thickness of the medium is uniformly high. The straight necks of the flasks allow Kapsenberg and metal caps to be inserted.