Have a look at both our S380-30 and S385-30 channel balances. These look identical, with the exception of the bottom balance shoe 'depth' measurement. You will need to measure the depth of your bottom balance shoe, the way it is shown in the diagram below, to determine which of the two balances would make the better match. Whichever one chosen will go with a 2950 option that supports a sash weight of 28-32 pounds.
Alternate view of 15-004