Left hand aluminum window slide number stamped in part is 2830

I believe we can replace this channel balance, but that stamp code only tells us the strength of the spring. To know what type you need, we need to see closer pictures of the nylon fittings on either end of the metal channel. We'll do our best to help from there. 

Thanks for the photos. Now, if the metal channel is 29" long (not including the fittings), then this looks like an S370-29. See if you agree. For a stamp option, go with 2830. 

Hey Keith. You can place the order right through the online store. From the S370-29 shop page, you can click "Add to Cart", then "Checkout" at the top right corner of the screen. Just be sure to set the quantity of balances you need, and the stamp option of 2830.