BESTFIT Mainspring 313B for Tissot 17.2, Gruen 455, Helvetia 105, Bulova 7AB & Kasper 500 - Alloy

BESTFIT Mainspring 313B for Tissot 17.2, Benrus "B", Bulova 7AB and Gruen 240, 270 & 455, Helvetia 105, Kasper 500 plus perhaps similar ébauche watches, white alloy. See image for precise characteristics, and notice as well that while those characteristics are the same across all 313B's, the models shown vary from envelope to envelope (don't ask me why). 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