KBK Mainspring #4082 for Waltham 7¼ ligne Factory No. 2238 - Steel

Kilb - Beck - Kuesel Inc (KBK) Mainspring #4082 for Waltham 7¼ ligne movements, Factory No. 2238, new in envelope. See images for precise mainspring specifications. Not very familiar with the supply house and would love to find at catalog for them. 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 and all watch parts are unconditionally guaranteed. Images do a pretty good job of representing the item.