Actually not made by a firm called Electra but by the German firm Kallmeyer & Harjes of Gotha as part of their "Electra Zinn" range of art metalware and dating to c1900-10. Established by Philipp Harjes (1860-1933) and Hermann Kallmeyer in 1887; this large factory employed up to 500 people in 1909 making a diverse range of metal ware both industrial, domestic and decorative. Their decorative wares are scarce and are rarely seen in the UK.
The company marks seem to be an eagle with wing spread looking back over it's left shoulder, but it seems that only the pewter art wares are marked with "Electra". I have not been able to trace any of their copper or brass decoratives wares to confirm this.
Interestingly I found pictures of this ordinary pewter dish decorated with a weak art nouveau design marked "electra" but with a makers mark GKFAF ? which doesn't fit the name Kallmeyer & Harjes? From the pattern number, this dish is probably earlier; so I wonder if the Electra brand was bought by Kallmeyer & Harjes, thus acquiring an arty decorative line without the expense of development ??
Any information is welcome and these beakers are for sale (at the time of posting) on my website;