HR Mainspring No. 423 for AS caliber 1234 - Steel

HR Mainspring No. 423 Mainspring for AS caliber 1234 movements, plus perhaps others (Bulova 5AD perhaps), steel, new in envelope. See images for precise mainspring specifications.  I specialize is hard to find watch parts so I usually have whatever you might need and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.