10mm x 1.0 Fine thread, male steel nut with non-threaded lead, 17mm long overall
This nut works with both SAE (45 degree/inverted/double) and DIN (bubble/ISO) flares
This is the standard European (German, DIN) style brake line nut
use with 3/16"/4.75mm (CNF-3)tube.
Found with both SAE and DIN flares.
It is now appearing everywhere, including late model American and Japanese cars.
If you have a Bosch ABS pump, you may have these nuts.
The 10mm x 1.0 nut is a bit larger and has a finer thread than the 3/8” x 24 unf American nut.
Used with UM14-3 union.
Caution, the 10mm nut will start in a 3/8” x 24 unf hole but will strip the threads as you tighten it.