ARS has two basic styles of chambers: One is a fully closed chamber in which the entire specimen to be tested is placed 100% within the chamber and all gas flow is controlled in and out of the chamber through ports on the chamber. Collection of 100% of the VOCs emitted from a specimen(s) is possible with such a chamber. The second VCC is an "open" chamber or what we call a "Guillotine" chamber. With this type of chamber, it is possible to collect volatiles from only a portion of a plant or specimen. The Guillotine design allows the user to selectively close off a part of a specimen in a chamber in which volatiles are to be collected in a clean (neutral) environment while allowing other portions of the specimen to be external from this sampling environment for reasons of size limitations, cross contamination or stimulus response testing.