Yellow tip replacement
If your tip is yellow, usually a yellow tip is right. I see you ordered a red tip balance. I'm going to freeze your order until we can verify the right balance.
Usually, the yellow tip is for a thinner balance than the Series 600 balance that you ordered. Usually, yellow tip balances are Series 900 (for tilt windows, at least). Re-measure your balance tube diameter. For 3/8", choose Series 900, and for 5/8", choose Series 600. The length of the tube will determine which balance from the Series you should choose.
Then, you probably want to weigh your window sash to choose a tip color. For each balance, we put a chart in the product description listing which weights can be carried by which color tip. See which tip is right for the weight of your sash.
Once you verify which balance you need, please call our customer service line. Their information can be found here.
You're welcome! Are the balance tubes all 25" long? If so, the yellow tip window would be best replaced with an S600-25 with a blue tip. You'd want to contact our customer service center once you verify the length. If they're not both 25" long, let us know how long the yellow tip balance is. You'll need a Series 600 spiral in that length.