Help Identify my Window Balance

Hello there, and thanks for contacting SWISCO. Based on the information you have provided I believe you are looking for either are S351-34 or S390-34 Channel Balances. The only difference between these two balances is the bottom nylon clip. As you can see from the product pages, the primary difference is that the bottom nylon clip on the S390-34 has a slightly greater 'depth' than the S351-34. Look it over, compare with your old part, and see what you think. 

Hi there. Received your sample and you will need the S390-34 side load balance. It is the better match for your needs. The spring weight code on the metal channel 33 3 is our 3330 for a sash weighing 18 through 23 lbs.

Sure. For the S390-34, the top nylon clip is the 19-002 and the bottom nylon shoe is the 15-001.