{"product_id":"marco-mainspring-2721-for-gruen-311-330-355-400-401-as-525-589-624-653-723-962-steel","title":"Marco Mainspring #2721 for Gruen 311, 330, 355, 400, 401, AS 525, 589, 624, 653, 723, 962 - Steel","description":"\u003cp\u003e\u003cstrong\u003eMarco\u003c\/strong\u003e Mainspring No. 2721 for Gruen 311, 330, 355, 400, 401, AS 525, 589, 624, 653, 723, 962 caliber movements and perhaps others as well, steel, new in envelope. See images for all supported calibers and precise mainspring specifications. 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":"C \u0026 E Marshall","offers":[{"title":"Default Title","offer_id":49140818968884,"sku":"PMS-CEM2721S-06","price":6.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0849\/3341\/1124\/files\/2026-05-2916.40.29.jpg?v=1780098371","url":"https:\/\/www.vintagetimeparts.com\/products\/marco-mainspring-2721-for-gruen-311-330-355-400-401-as-525-589-624-653-723-962-steel","provider":"Vintage Time Parts","version":"1.0","type":"link"}