S351-16 vs S390-16

Thanks for posting, Andy. The major difference between our Series 390 and Series 351 channel balances are, indeed, in the bottom shoe. To determine which one you have, please look at the measurements for our 15-001 and 15-002 bottom shoes and note their depths. As you can see, they are 1-1/8" deep and 1" deep, respectively. Which measurement more closely resembles your own shoe?

You might also want to double check the length of your metal channel. Based on your stamp, it should be 17", not 16".

If your metal channel is 16", and your stamp reads 1620, then your balance may have been cut down from its original length of 17". Please just confirm one more time that only the metal channel is 16". Do not incorporate the plastic attachments in your measurements. If it is, then I will need to know the weight of your window sash in order to select an appropriate stamp option.

Thanks for getting back to us, Andy. I'd go with the 1530 stamp option, which has a window sash weight capacity of 10 through 12 pounds.

Please keep in mind that the weight range information is based on 2 balances per sash. Balances are designed assuming friction in the jamb weather-strip will carry a portion of the sash weight. Suggested sash weights are approximate.