I found this recently after searching for a well proportioned chronograph for years. This watch has an impressive case size of roughly 39mm x 12mm x 45.5mm, and a very clean and symmetric dial design. This watch was produced in 1998. The reference for this watch is 39-31-07-07-04, it uses the Glashütte Original / GUB 39-30 movement. This watch is quite rare, since it is from when Glashütte Original still had a fantastic line up of flieger watches.