I have a mystery coax relay (no letters or numbers) which vaguely resembles the above (it also has a Y-shaped connector layout), but with tri-angled (and for some reason, scalloped) sides. The solenoid is also different insofar as it is perpendicular to the body with a piston action. It does have an inspection facility which has revealed the moving contact to be disc-shaped. Chunky, shorting and with 3 N(F), it looks like it might have a higher spec than my current bladed ones, though the solenoid is currently o/c.
Any ideas? Worth rewinding or just scrap :>)