Ordered wrong channel balance - need help identifying correct part

Believe it or not, I just had another customer with pretty much this same configuration. You must have bought your window at the same time as he did.

We can help with this balance, but it has to be a custom order since this isn't a stock design. Before we go any further, though, I need a bit more information. First, can you confirm the length of the metal channel? I'd also like to know the exact weight of the sash your balances support. Finally, how many did you need?

Perfect, thank you so much! What I'll do now is email you two purchase links and price quotes for the requested balances. You can use these to place an order on our site.

One thing to note is that the 12" balance you need is unfortunately out of stock. There is an expected lead time of approximately 4-5 business weeks. I apologize for the inconvenience.

These balances will come with the 15-014 pre-attached. This shoe appears to match what you have in your photos, but if you have any doubts then please let me know.

Thanks for getting back to us. Your knife shoe definitely looks broken. You will need to compare the dimensions of an unbroken version to the 15-014, I don't think a damaged one will give you an accurate read. 

As for the spring, I've never personally seen one with it, but I do know of it. Its purpose was to keep the metal fork press against the window track to keep it locked when removing the sash. 

Weathershield has exclusive rights to their knife shoe that is very similar to our 15-014, which is from the balance manufacturer. We believe it should work fine in vinyl jamb liner.