Channel balance replacement

Question

The channel balance replacement I need looks just like the Series 770. The imprint on the old part is 21HD BSI JL. I'm guessing D is the weight range but am wondering if HD means something else.

Bob · Accepted Answer

Thanks for posting. Be sure to measure the metal channel to determine the length you need. Some older balances use different stamp codes; the safest thing to do is obtain the exact weight of the window sash that uses these balances, then match that weight with one of the weight ranges listed alongside each stamp option on the balance shop page. Please send us pictures of the balance if you're uncertain the stock Series 770 is exactly what you need.