This Columbus Instruments PEGAS 4000 MF Gas Mixer is in great condition and is guaranteed to be functional with a 30-day return policy. This unit came from a local lab that had surplus lightly used equipment. We urge customers to view all photos as they show overall condition, included accessories and useful information. Listing only includes what is shown in photos. We will be happy to provide additional information as well as photos so please feel free to contact us with any questions. Columbus Instruments' PEGAS 4000MF Gas Mixer is a multi-gas mixer, which can blend from 2 to 4 gasses in a precise mixture available upon demand. The PEGAS 4000MF uses thermal mass flow controllers to provide an exact flow of each component gas. The system is equipped with an internal microprossor to perform all of the needed calculations and to provide signals to the flow controllers. The user only needs to enter the total flow and the concentration of each component gas