Pardon me for writing in English...
These squibs were made in the 1950s and 60s by
Feuerwerk-Fabrik Fritz Sauer, founded in 1863 and located at Wiesbaden at that time. The name "Sawie" is short for "Sauer Wiesbaden". The factory was founded in 1863 and is still active on a different location (Gersthofen). Peter Sauer, the current owner, is a good friend of ours.
Here is a technical data sheet by Sauer with more details:
My buddy sureshot and I do a video project every year (since 2008) where we shoot various old fireworks and film them. Last year we also had two of the Sawie squibs:
There also were two smaller variants, Schwärmer C (medium) and Schwärmer klein (small).
They are surprisingly powerful and still work like a charm even after all these years.
I really love these old fireworks.