Need DL6 coil spring for vinyl window.

Hello there. This looks like a Series 140 Coil Balance system. To know what spring weights to select, weigh the window sash this system helps support. Give me that exact weight and I can work things out for you.

Great. If the sash weighs exactly 20 pounds, you can use the S140-10 10 pound systems, one on each side of the sash. This will give you 20 pounds of overall support. Let me know if you have further questions!