Unique pat no 2792588 ( the second to the last number is a guess)

This looks like an older builder's grade window balance. There's a good chance this exact model isn't made anymore, but I recommend that you consider our Series 500 as a substitute, along with a bottom bracket like our 17-012.

One thing to note is that the Series 500 has a 9/16" diameter outer tube. If yours is smaller, let me know.