The lexicon of the top500 ( The Encyclopedia for Classification Codes ) explains the codes and definitions in the world of economical classifications.
NAICS Code 3391 Medical Equipment and Supplies Manufacturing
The NAICS Code 3391 is described as
Medical Equipment and Supplies Manufacturing It belongs to the code group
NAICS Code 339 Miscellaneous Manufacturing
To this Code "3391" belongs the sub codes
NAICS Code 33911: Medical Equipment and Supplies Manufacturing