Nu Air Side Load Single Hung Window Balance Spring

Thanks for contacting us. When measuring the balance, it's measured from metal to metal only, excluding the nylon fittings. So the 30" is correct. That said, have a look at both our S380-30 and S385-30 channel balance. The only difference between these two balances is the 'depth' measurement of the bottom balance shoe. You will need to measure the depth of your bottom shoe, the way shown in the diagram below, to decide which of the two would make the best match. Whichever one chosen will use a 2950 option that supports a sash weight of 28-32 pounds. 

Alternate view of 15-004

Hello! Manuela isn't here today but I can help. I'm not sure what a corner stopper might be, but it sounds like you're referring to the top sash guide. We carry a ton of different types, which you can see here, and the Series 380 itself is compatible with many of them. We aren't able to narrow it down much without more information. 

I recommend looking through our selection first to see if you can find a match. If not, I'll need you to remove an undamaged version of your top sash guide and take a couple pictures of it for us to review. We would appreciate it if you took your photos from the front and side; think of it like a mug shot. That will allow us to determine what style you have and we can do our best to match it up. Dimensions would also be helpful, if you're able.

Sounds good to me! I'll be here if you need me. Thanks again for reaching out to us and please let me know if you had any follow up questions.