{"product_id":"samsonspring-mainspring-no-12a-for-gruen-caliber-857-steel","title":"Samsonspring Mainspring No. 12A for Gruen caliber 857 - Steel","description":"\u003cp\u003e\u003cstrong\u003eSamsonspring \u003c\/strong\u003eNo. 12A steel mainspring for \u003cstrong\u003eGruen\u003c\/strong\u003e caliber 857 movements plus perhaps others, new in envelope. See images for precise mainspring specifications. These are for very old Gruen movements, 1920's and before. 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.\u003c\/p\u003e","brand":"Samson","offers":[{"title":"Default Title","offer_id":49119159517492,"sku":"PMS-SAMS012AS-05","price":7.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0849\/3341\/1124\/files\/2026-04-3010.47.39.jpg?v=1777571380","url":"https:\/\/www.vintagetimeparts.com\/products\/samsonspring-mainspring-no-12a-for-gruen-caliber-857-steel","provider":"Vintage Time Parts","version":"1.0","type":"link"}