Friedrich Speidel "Bi-Metal" Double' Bracelet, 1940s (?) Flea Market Find

I bought this at the last minute, just before I left the market on Sunday. It was originally priced at $15, but the dealer made a mistake and told me $10. He honored his error even after he realized he goofed. The marks went unrecognized...
This bracelet is light in weight and the gold plating is 99.9% perfect. There is an extra stamp on this one that's not on my silver bracelet: what looks like a lower case "f" on the bottom left. According to what I read on the web, there is not too much of his jewelry around because much of it was lost during WWII.

Thanks for looking, CW friends!