Casey from SWISCO responded:
June 13, 2014
Hi! For the Series 750 you will need 2 of the S750-28 with stamp 27R.
A pair with option 27R will carry a window sash weight range of 10 through and including 19 pounds. This 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. |