Material is brass (copper alloy is the same thing), but the field is having problems with material definition.
A one-piece metal item, usually tubular, flanged at one end, the other end open. It is used primarily for lining and reinforcing the edges of holes. The unflanged end is designed to be inserted through a hole and crimped to form a mating flange. Excludes grommet, metallic and eyelets which are components of pushbutton, turnbutton and turnlock type fastners.
Classification: Hooks, eyes and eyelets, of base metal
NSN 6105-01-369-3069
NSN 6105-01-479-5054
NSN 6130-01-406-2946
NSN 5965-00-078-5770
NSN 6240-00-971-8193
NSN 5965-01-193-0420
NSN 5985-00-991-0604
NSN 5985-00-666-2987
NSN 5999-00-408-3931
NSN 6220-00-169-6516
NSN 6220-00-681-0483
NSN 5895-00-617-6340