BESTFIT Mainspring 713E for Font 60, AS 970, Kurth 257 & 258, Amida 515 + many others - Alloy

BESTFIT Mainspring 713E for Font 60, AS 970, Kurth 257 & 258, H. Becker 80 movements, plus perhaps similar ébauche watches, white alloy, new in envelope. See images for precise mainspring specifications. I likely have several of these (perhaps way more than several) so the envelopes may look slightly different that what it shown, and you can ignore any remarks a previous watchmaker may have scribbled on them. I specialize in 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.