Silver metal cap
Cartridge filling
Medium nib (No number, just says Medium Esterbrook made in USA)
Black body with a metal ring at the opening of the body where the section screws in.
It came with an empty Esterbrook cartridge. Cartridge has a yellow ring on the top that can come on and off.
Like I said I think it is a late model dollar pen as I saw an ebay auction for a lot of 12 new ones that were carded along with 6 cartridges and they were printed with $1 each on it.
What modern cartridges do these take? I can always refill the old cartridge with a syringe but if someone makes something compatible then it would be nice to have spares.

Charlie