A home owner from USA says:
August 9, 2016
I was given these part numbers.. FA2830 and FA3540. Hope this helps. One measures 29 inches and the other 35 inches. 1/2 Width.. Non-tilt window
Paul from SWISCO responded:
August 12, 2016
Hello, Arturo. Please see our Series 395 channel balance. This appears to match your pictures.