These Musser E1904V springs connect the two ends of your marimba, vibraphone, or xylophone bar cord, keeping it taut so the bars don't sag. They are made for all Musser keyboards, but they're usable with any instrument that requires bar cord.
You must tie each end of the cord to one of the loops on this spring. While this old design does make it less convenient to pack the bars up, it does mean that you only need one pack per instrument.
