PM Mainspring No. 427 for 18 / 19 ligne Langendorf caliber 1901 - ONYX Steel

PM ONYX steel mainspring No. 427 for Langendorf (LANCO) 18 / 19 ligne caliber 1901 movements and quite likely others, new in envelope. See images for 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 suitable job of representing the item.