These Tau demo units are full production cameras that were capitalized by FLIR for internal use. Production cameras are fully operational, and meet or exceed FLIR's Acceptance Test Procedure (ATP) criteria for Tau. They are no different from Tau cameras otherwise offered for sale by FLIR to the general public.
The term "Demo Unit" implies that various groups within FLIR -- including Sales, Engineering, Marketing, and others -- acquired Tau cameras in support of FLIR activities such as trade shows, customer demonstrations, optics development, beauty shots (for ads and website), reliability analysis, and many other uses. A good example can be seen at the Tau webpage under the detection/recognition/identification (DRI) tab. All of the images at this location were made using eight Tau demo cameras with different optics, to provide and compare examples of the different lens fields of view.
In a few cases, demo Tau cameras have been temporarily loaned to prospective customers for evaluation prior to purchasing new Tau cameras. Even so, the majority of demo Tau cameras have experienced very little actual use. There is no internal clock or timer to know exactly how long a given Tau has been operated. The nature of the thixotropic magnesium used for the Tau camera frame and rear cover sometimes makes the cameras look old and worn, but this appearance is entirely cosmetic. FLIR offers a reduced warranty period -- six (6) months -- for demo units.
Tau 320 cameras were originally offered by FLIR at prices ranging from $ 6,000 to $ 8,000 each, with longer focal length lens models costing more. The demo units offered for sale are at prices about 20% of original. One advantage of Tau cameras over newer models is that the optics have an average f/number of about 1.25 (vs. f/1.0 for newer models). Depth of focus improves with higher f/numbers. In addition, several of the narrow field optics are germanium, which is optically superior to the more recent lenses used that are fabricated using molded chalcogenide glass (which has cost and producibility advantages).