Reasearch leads me to believe this is a 1939 American Clipper "A". Yellow gold on original bracelet and shows no signs of wear. Case and band are as reflective as a mirror with no scratches, brassing or scuffs. Crystal is perfect. Dial is a bit chalky in appearance, likely from a poorly orchestrated cleaning.
Movement bears both a shield for 1939 and a crescent moon for 1938.
Online auction purchase - it was initially listed as a women's watch (nobody was watching) - $25 including shipping. Inside of back has a jeweler's mark (sharpie pen) indicating the last service was in 2005. Keeps perfect time.
Oh what a wonderful find! I have seen a few of mens watches listed as womens.
1939 Bulova American Clipper.
1939 Bulova American Clipper with original bracelet for this price, that's awesome
Here is my thinking on AC "A".
It is advertised as "Bracelet" or "Pigskin" band. Pigskin is seen identified as AC "B"

Black Face on bracelet is an AC "C"

Yellow gold with white face on bracelet with engraved case and bracelet is an AC "F".

This ad from 1936 lists pigskin band on yellow gold or mounted on bracelet in either yellow or white. I'm not prepaired to go here yet, but suspect bracelet version in white gold was either the missing "D" or "E" variant and perhaps the other is black face on pigskin or in white gold.

I would hesitate to assign either "A" or "B" to an American Clipper without a verified original band, but subject watch has it. American Clipper "A" for me.
I agree it's an American Clipper, I think it has an original bracelet but I don't see it advertised as an "A" anywhere in this configuration.
1939 Bulova American Clipper
In reply to I agree it's an American by Geoff Baker
I went by process of elimination for the variant letter. Earliest ad shows three variants based on band and gold color. The pigskin in yellow gold is later identified as "B". No further mention in ads of bracelet model in white gold. "C" is black face on bracelet in yellow gold; leaving "A" as bracelet/yellow gold/white face.
In reply to I went by process of by neetstuf-4-u
Your reasoning make sense, I prefer to go by the ads. I'd rather not speculate on variants.
I'm thinking American Clipper 'A' also.
Very nice with original band too. One thing about the American Clippers I've noted over the years, is that the dials always look beat up. Very hard to find an example with a decent dial.
Just reading through this post and realized there isn't actually an ad for "A". Here is an ad for "D" which appears to match this watch.

In reply to Just reading through this by Kathy L.
Well done Kathy. Can't argue with the ad; looks like you've confirmed the variant and I stand corrected.
AC "D" it is.