BESTFIT Clock Mainspring for German Travel Alarm Clocks 3.00mm x .22mm - No. T300-6

Bestfit System #77 Clock Mainspring for German EMES 20 to 23 clocks, Dennison 21 x 2 x 22½, TIME side spring, Regular tongue end, No. T300-6, 1950's or newer, new in envelope.  These look like alloy mainsprings to me. See images for precise mainspring specifications. I specialize is hard to find watch & clock parts and all parts are unconditionally guaranteed. Images do a pretty good job of representing the item