Penn Engineering Press in Blind Threaded Standoffs
TSOS-440-437 
.112-40 (#4-40) Thread Size, Pitch
300 Series Stainless Steel
For Sheets as thin as 0.25 in.

Overall Length .437 in.
Press in Hole Size .166 in.

Each quantity bid is for 50 pieces pulled from a bulk package.

These are fairly small, see second photo for size comparison to a us penny.

Manufacturers datasheet link:
https://catalog.pemnet.com/item/thin-sheet-thru-hole-standoffs-types-tso-tsoa-tsos/-sheets-as-thin-as-025-types-tso-tsoa-tsos-unified/tsos-440-437