{"product_id":"usr-mainspring-for-longines-12s-caliber-18-79-18-80-18-89-18-90-steel","title":"USR Mainspring for Longines 12s, caliber 18.79, 18.80, 18.89, 18.90 - Steel","description":"\u003cp\u003e\u003cstrong\u003eUSR \u003c\/strong\u003esteel mainspring for 12s (18 ligne) \u003cstrong\u003eLongines\u003c\/strong\u003e calibers 18.79, 18.80, 18.89, 18.90 pocket watch movements, and perhaps others (including the ABC variants of these calibers), new in envelope. I likely have several of these so the one you get may differ slightly from the images.  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":"USR","offers":[{"title":"Default Title","offer_id":48909312098612,"sku":"PMS-USR1879S-09","price":12.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0849\/3341\/1124\/files\/2025-09-3017.17.00.jpg?v=1759277990","url":"https:\/\/www.vintagetimeparts.com\/products\/usr-mainspring-for-longines-12s-caliber-18-79-18-80-18-89-18-90-steel","provider":"Vintage Time Parts","version":"1.0","type":"link"}