Low = "Low Pitch" = modern intonation, where a concert A=440hz.
A = "Alto"
You neither have an alto/soprano pitched in A -- which would be interesting, to say the least -- nor do you have a saxophone with a low A key. In the former case, there isn't an alto/soprano in A. In the latter case, all you have to do is count the toneholes on the bell.
The horn you have is a Martin Handcraft Standard stencil and, without the neck, it looks like an Eb alto. It's easy to tell the make/model because of the unique offset forked Eb vent under the low D key. As the Handcraft Standard was produced from 1935ish to 1938ish, your horn is either late 1930s or early 1940s. The serial number doesn't help on a stencil. Why I place the date of manufacture toward the end-run of the Handcraft Standard into the 1940s is because US stencils were generally introduced after the non-stencil had been around for a bit.
For more info, you might want to check out my original
Saxpics.com article,
my little photo essay on the Martins and
Edwin van Druten's The Martin Story website.
Since I moved the thread into the appropriate forum, let me also mention that the horn is valued at somewhere around $150 to $200. You definitely need all new pads, corks and felts ($400 to $700). Based on my experience with older Martins, you probably also need all new springs ($150-$200). The silver plate can be cleaned, if desired, either by a shop ($50-$150) or by yourself with a liquid, non-abrasive, non-tarnishing polish for silver plate (don't use Brasso, unless you like black horns). I don't see any other major damage, but you also have only two pics. Maximum value of the horn, after all repairs, is going to be less than $500. If you're just going to sell the horn, don't do anything with it. Just repost it on eBay.
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Shenkelaars did not produce their own saxophones. They purchased horns from other companies and stenciled their name on them. I can't tell you anything about the horn without some pics. Check out the rules and FAQs we have listed to get an idea of what would help us to help you.