An Iron Cross 2nd Class 1914 by M. Flex & Sohn of Hamburg | eMedals
Although they spell it as M. FLEX & SOHN. Attached photo shows correct spelling of this jeweler´s name on the carton box for Feldehrenzeichen.
Maybe there were two jewelers in Hamburg, one called M. FLEX and second one M. FLECK, but I doubt it. Flex is just incorrect spelling, IMO.