Window balance

Thanks for posting! The window is likely hard to open because the balances are worn or damaged and/or the top sash guide needs to be replaced. To determine if it is the top sash guide, you'll need to examine the guides on the top left and right corners on your sash.

In regard to the stamp, you'll need to confirm your sash weight to determine if the 2740 would be a viable option. We typically recommend replacing a balance with what is already installed in a window since the balances are made to support specific weight ranges; they are not easily interchangeable.

There is a list showing the weight ranges each stamp can support below the product description of the balance.