This is an original vintage Service Manual 8 1/2" X 11" soft cover with 28 pages listing the Yale Pin Tumbler Lock numbers and their key code or key cutting data for that particular lock. The numbers for the locks start with # 1000 and continue in sequence to lock # 28086. All you need to do is get the number off of the lock and you can look up the key cutting code for that lock. As the instructions say "by providing keys to replace lost keys, without tearing the lock apart or mutilating the lock in any way." This was for locksmiths only. This lot came with other automobile lock and key equipment literature, and code books I have been selling and the latest it went to was 1935. Buick Oldsmobile Pontiac Chevrolet Ford Cadillac LaSalle Dodge Jordan Peerless Sterns Knight Chrysler Packard Hudson Oakland Willys Six Essex Terraplane Nash Falcon Knight De Soto Marmon Willys Knight Overland Windsor Tire Lock Bauer Wheel Lock Oaks Tire Lock Mc Kinley Tire Lock Corbin Padlock Plymouth 29 30 31 Whippet Hupmobile and Basco Padlock. Chrysler Dodge Plymouth Durant Willys-Six Black Knight Locks Rockne Moon Independent Padlock Auburn Cord Franklin Stutz Star Rickenbaucher ( Rickenbacker ) Studebaker Pierce Arrow Erskine and Bud Tire locks. hot rod hotrod ratrod rat rod flathead Ford racing 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1934 1935 28 29 30 31 32 33 34 35 Hollander interchange accessory accessories identification data motor engine ignition MARC MAFCA AACA Hershey Pa. Region manual auto automotive car Simon Code Finder antique classic club Model T ford Model A Ford key blank types door glove box trunk cars trucks vehicles motorcycle ID identify literature books compartment Yale Jr., Basci Yale Pin Tumbler Lock padlock locksmith tool tools restoration restore antique See my other lock and key related items.