Yellow tip balances

Thank you for reaching out to us. This looks like a typical spiral balance. Can you confirm the outer white tube diameter? You don't want to measure just the naked spring shown here. If there's an identical window in the house, you can use that as a reference. 

We don't sell a spiral balance with that kind of tube diameter. We only have two options which would be the 3/8" Series 900 or 9/16" Series 600. They don't make any other sizes for this style of balance.

The only 1/2" thick pivot shoe we have is the 15-046 but we recommend you remove yours from the window track and measure the thickness and width to get an accurate measurement. The related video will walk you through the removal process. 

I'm afraid we can't promise the 3/8" Series 900 will work for you since the specifications differ but it would be the closest option, yes. You can find our return policy here just in case. 

The Series 600 balance goes with the 15-046 pivot shoe and looking at your photos and the channel being 5/8", I would recommend you go with the S600-20 and the red tip for your 16.5-pound sash.