Please see attached pictures. There are three sizes of single pane windows with balances marked 2340, 2820, and 3440. Please identify which of your part numbers these are. I think they are series 351 but i'm not sure.
Thanks,
Sandor
Paul from SWISCO responded:
July 20, 2016
Thanks for posting, Sandor. I think you could have either our Series 390 or Series 351 depending on the size of your shoe. You will need to measure yours and compare it to our dimensions to be sure.