Need 10 pairs of these

Hi, Barbara. 

With this combination of attachments, you could have either an S380 or S385 channel balance. You’ll need to measure as shown below. The Series 380 has a 1" bottom attachment, and the Series 385 has a 1-3/32" attachment. 

Does your metal channel have a stamp on it? If it doesn't, you'll need to weigh your sash to determine which option you'll need. There is a chart on the S380 and S385's product page that explains how to choose your option based on the sash weight. 

Comparison of the S378, S380 and S385 balance shoes.

Thanks for getting back to us. If your old stamp reads "28B," then you want the 2820 stamp. In this case, B = 20. The first two digits are not a direct representation of the weight of the sash, they actually only tell you the height of the visible glass. I couldn't tell you why they think you need to know that, I personally think it's just confusing, but that's the way they do it.

If you have any doubts, you can always weigh your sash on a scale and check our chart. That will tell you for sure.

Finally, all of our balances are sold fully assembled and ready to install out of the box. All pricing can be found on each product's respective store page.