2830 BSI Window Balance ID

Thanks for contacting SWISCO. I can't be totally certain from your photos but this looks like it might be either our Series 351 or Series 390 Channel Balances. The only difference between the Series 351 and Series 390 is the 'depth' of the bottom nylon shoe. The Series 351 bottom nylon shoe has a depth of 1", whereas the Series 390 bottom nylon shoe has a depth of 1-1/8". Compare with your old balances and see what you think matches best.

Measure the length of the metal channel (but not including the nylon attachments) to know which length balance you should select. Finally, the stamp option 2830 corresponds to a window sash weight of 16 through 23 lbs. If you are unsure this is right, weigh your window sash to see if it falls in this weight range.