I have been familiar with the Esterbrook Reliefs (CS made).
I have also seen 14C Relief "renew points" (removable). But today's mail brought a surprise. A gold plated trim, UK made, Esterbrook in solid blue with a 14CT Relief "renew point".

My guess is that this is a 50s pen. It reminds me of the late icicles.

Undocumented in Esterbrook.net, hence ultra valuable, Brian? (sumgai scream)

Cool pen!

I've seen this word before: sumgai - what does it mean?

According to one online pen glossary:
'Sumgai. A mythical figure first identified on the Zoss list, someone who arrives at a sale or shop ahead of you and buys up all the good pens. As in "We had some nice pens here, but last week Sumgai came in and bought them all."'

At $20 this was a sumgai purchase

Yeah, those are cool pens. I'm envious. I have one in green, and the Regina Martini book shows them in red and black, so I surmise they were also made in copper and grey as well. late 50's is probably about right, they have that later cheaper feeling plastic to them.

Nice find!

Best-
Brian