Photo and description are kindly provided by Dr. David Chinn, for an upcoming ARTP article.

“Spirometer display showing tumblers for program setting (upper one), setting the time interval for the FEV (lower left hand) and BTPS temperature correction (lower right hand). The socket below the upper tumbler links to an XY plotter to print the flow-volume curve in delayed time. The jack plug socket marked ‘record’ provides an output to the cassette recorder.”