Extended-Travel Channel Balance Quote

Thanks for posting. Based on the end fittings and length I think this is just a standard channel balance, not the Extended-Travel variety. Specifically this appears to be either an S351-18 or S390-18, depending on the depth of the bottom nylon shoe. See the image below for an explanation. In either case, for a stamp option choose 1720.

Comparison of the S351 and S390 balance shoes.