Help Identify spring

Hello,

You have the 300 Series Danvid windows, and I suspect your sash may not be removable. You'll need to replace the spiral balances by unhooking the bow tie at the end of the spiral from the bottom sash clip. To see the clip, you'd raise the sash and have someone hold it up while you pull away some of the bottom bubble seal at the end of the bottom sash. 

Then, look up under the sash, and you should see the bow tie anchored in the sash clip. Place the 75-005 tool in the hole at the end of the spiral and work the bow tie from the sash clip. The spiral might spin to release the tension. 

Next, unscrew the top screw holding the balance tube, lower the sash, and try to pull the balance tube and spiral from the sash. Once the balance is removed, take a look and confirm if the specifications match the (3/8") Series 400 or (5/8") Series 500. See the guide below. Thank you! 

Guide: How to adjust a spiral balance on a non-tilt window