Channel balance for metal window. Non tilt

Hello, I think you may have either our Series 351 or Series 390 half inch channel balance for non-tilt windows.The difference between the two lies in the shoe. The series 351 channel balance has the 15-002 shoe while the series 390 channel balance has the 15-001 shoe.

The 15-001 shoe is 1/8" larger from front to back.

Comparison of 15-001 & 15-002

You'll want to measure the length of the metal channel to choose the correct length and then look for a number printed on the metal channel that indicates the spring strength.