The Ithaca Model 37 was the last long gun designed by John Browning.
As such, it's an American classic.
The Model 37 is the last American shotgun still made of solid forged and milled steel, and American walnut.
It was used over the years by the Navy SEALs in Vietnam, the LAPD, and the US military in WWII.
It's an unusual design in that it both loads and ejects from the bottom of the receiver.
The Ithaca is about bullet-proof, with the only problems were some tendency to develop cracks in the butt stock where it joins the receiver.
The Model 37 is an "old school" design and isn't as easy to field strip as newer guns, and due to the barrel and magazine design, you can't add an extension, or change to a shorter magazine.
So, the magazine length you buy the gun with is what you have to live with.
There are few accessories available, so you may have trouble finding other stocks, barrels, fore arms, or lights, etc.
The guns have had a 3" chamber for some years.
To find out where to buy, I'd contact the new factory and ask who their distributors are.