GENbag consists of an airtight bag made of transparent plastic. Used with a generator sachet, it rapidly produces the appropriate atmosphere for the culture of bacteria which require either an anaerobic, microaerophilic or capnophilic atmosphere i.e. requiring carbon dioxide. The aluminium GENbag generator sachets function without the addition of water or a catalyst (no hydrogen is produced). They provide the user with a high level of practicability and security. The GENbag anaer, microaer and CO2 generator sachetsall contain the same chemical compounds i.e. activated charcoal, sodium ascorbate and other organic and inorganic compounds. The gas compositions obtained (oxygen and carbon dioxide) are adjusted by the quantity of the chemical compounds contained in each sachet, which absorb oxygen and release carbon dioxide.