{"product_id":"hamilton-dynavar-10s-mainspring-for-917-921-923-945-20433-alloy","title":"Hamilton Dynavar 10s Mainspring for 917, 921, 923 \u0026 945 No. 20433 - Alloy","description":"\u003cp\u003e\u003cstrong\u003eHamilton \u003cem\u003e\u003c\/em\u003e\u003c\/strong\u003e\u003cem\u003eDynavar \u003c\/em\u003eFactory Mainspring for 10s Movements, more specifically the models 917, 921, 923 and 945, Factory No. 20433, alloy, new in envelope. See images for precise mainspring specifications. I likely have several of these so the one you get may differ slightly from the images. I specialize is hard to find watch parts and all watch parts are unconditionally guaranteed. Images do an adequate job of representing the item. \u003cbr\u003e\u003c\/p\u003e","brand":"Hamilton","offers":[{"title":"Default Title","offer_id":47451959722292,"sku":"PMA-HA20433A-08","price":20.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0849\/3341\/1124\/files\/2026-05-13_16.17.05.jpg?v=1778714248","url":"https:\/\/www.vintagetimeparts.com\/products\/hamilton-dynavar-10s-mainspring-for-917-921-923-945-20433-alloy","provider":"Vintage Time Parts","version":"1.0","type":"link"}