Robusta Mainspring No. 1188 for Benrus caliber BU - Steel

Robusta No. 1188 steel mainspring for Benrus caliber BU bracelet movements and perhaps 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 pretty good job of representing the item.