The Astra IIIB has been made for us in China since 1986 and it is produced in accordance with our specific quality guidelines. It has somewhat revolutionized celestial navigation because never before has such a high quality, accurate metal sextant been available at such a low price. Over 26,000 sextants of this model have been sold in the US alone, far more than any other serious sextant. Its popularity has spread throughout the rest of the world as well, making it the most recognized (and supported) sextant worldwide.
The Astra IIIB was produced under the technical drawing GLH 130-40, and some models made for internal consumption still bear that identifying mark.
Knockoff models. As might be expected, the ease of internet marketing and international delivery has prompted some other Chinese factories to clone the GLH 130-40 with disappointing results. Some are pure junk. Such models can be seen on websites such as Alibaba and Made in China for prices from $300 to $600, caveat emptor (buyer beware).