Model S400. A horizontal, dry, rolling-seal volume displacement spirometer. Manufactured by Graseby-Andersen which later marketed it under the brand name Spirotech. From http://www.sensagent.com/ebay/search-item.jsp?iId=151089920087&sId=-1&dl=en
Model S400. A horizontal, dry, rolling-seal volume displacement spirometer. Manufactured by Graseby-Andersen which later marketed it under the brand name Spirotech. From http://www.sensagent.com/ebay/search-item.jsp?iId=151089920087&sId=-1&dl=en