Here we have up for sale an ORIGINAL, 1961, Twin Disc Clutch Company "Hydrodynamic Drives Applications" Engineering Catalog.  Catalog has neat illustrations as well as having in-depth engineering/application information about these drives (please see pics). Catalog is clean with 66 pages and has NO tears or tatters.  Catalog is in NEAR MINT overall condition.  FREE S & H.  Thanks for viewing....Triple K