I'm trying to figure out what this case is.

Any help would be appreciated.

Regards,
Larry

The number is .421 and I think it is the serial number as it is on the bezel and the swing out.

Nickel would be my guess

Try this:
Looks like Dave has it right again.

Crescent Grades
Case Grade Case Material
Extra 14K Gold-Filled case claimed to contain "... about TWICE AS MUCH GOLD as any other filled case heretofore made."
(Star & Crescent Moon Trade Mark) Gold-Filled case, guaranteed for 20 years
Planet Gold-Filled case, guaranteed for 20 years.
(Star & Crescent Moon Trade Mark) Nickel case

Yes def nickel. Its a nice one though, the last one of those I had wasn't worth keeping...

Thanks everyone!

Regards,
Larry