This is a COPY of the ORIGINAL.

Service Manual Overlock Machine Revised June 1987 Superlock 503-523-534-504 - 50 pages

Our manuals are printed copies, sized 8 1/2 × 11 inches and bound with a clear plastic front cover, a plastic comb spine so that they can lie flat when opened, and a cardstock back cover. 
Most are enlarged from the originals.