After 1951, the Lange VEB company was enveloped by the GUB.  Still, the quality of the caliber 28 was recognized and the use of caliber 28.1 (the same caliber with central sweep seconds) was put into use in the GUB's higher-end watches.  While both the dial and movements of these watches were signed "GUB," the caliber was marked as "28 Q1", and these were produced by the former employees of Lange & Sohne.  The "Q1" marking, which you'll see on both Lange VEB and GUB watches with the Cal 28 inside translates to "A1", meaning they contain movements of the highest standards, just like you'd see on older Lange pocket watches.  GUB continued the production of watches with the Cal 28.1 through 1957 and produced 16,396 units.  These too are extremely difficult to locate.  After Caliber 28.1 was retired, the GUB went on to create many of their own calibers that simply pailed in comparison to the Lange 28. Of course, these watches should not be truly considered vintage A. Lange & Sohne watches because neither Lange VEB and most certainly not GUB were owned by the Lange family.  But, they did indeed use a movement that came from A. Lange & Sohne and one built to their standards.  These Caliber 28 watches represent a very important time in German and Lange history as they really are considered the first in-house Lange wristwatch movement.