29D 30" spring part; Brand nuair

We sure do. Thanks to your photos, I was able to narrow down the list of possible replacements to just two balances: our S351-30 and S390-30. The only difference between them is the depth of the bottom shoe, so you'll have to measure yours to confirm the better option.

Regardless of which one you go with, I also recommend choosing the 2940 stamp option when prompted. This will match your old 29D stamp.

All orders can be placed directly from our site at your convenience. All you need to do is visit the store page in question and click "add to cart." 

We do have a return policy, yes. You can see it here. 

I can't determine that, unfortunately. Like I mentioned before, you have to measure your hardware and refer to the dimensions we show for each product.

I'm afraid I still don't know what your dimensions are, but these photos do change things. I see now that your top and bottom nylon fittings have little tabs on the side. That means that instead of the two products I mentioned before, your choice is now between our S380-30 and S385-30.

The same principle applies, though. You need to measure the depth of your bottom fitting to confirm the best choice. The S380-30 bottom fitting is 1" deep and the S385-30 fitting is 1-3/32". We have detailed dimensions on each product's store page that you can use as a reference. It's a subtle difference, so it's not something that we can eyeball in a photo.  You will have to measure as carefully as you can and use your best judgement.