These are original Singer List of Parts booklets printed for the beloved Singer model 20 Sewhandy machines. These List of Parts booklets are very rare and contain diagrams, specifications, and part number lists for the specified machines. Each book is 8.5" tall and 5" wide.
The 20-1, 20-2 book was printed in 1937 and has 23 pages.
The 20-1, 20-2 and 20-10 book was printed in 1950 and has 26 pages.