Stability Chamber is a machine, similar to an oven, in which the temperature & humidity are controlled at a particular pair of set points. 

To prove the shelf life of a product in a certain market, the manufacturer must store it at a relevant temperature and humidity for a specified time. This is done in a stability chamber also known as a stability cabinet. 

Each market’s regulatory authority specifies what temperature and humidity conditions should be used and how long the samples are to be stored, e.g. 6 to 12 months minimum. During this period the samples are tested and their potency and degradation measured and recorded. This is called stability testing.