Caldwell channel balances

Welcome to SWISCO.com. Your 26" balance is either Series 380 or Series 385. You'll need to measure the bottom shoe in order to tell which. Take a look at the photo I'm attaching below, and measure as shown. If you come up with 1", you have the Series 380. For a 1-3/32" shoe, you'll need a Series 385. To determine the stamp option, you should weigh your sliding window sash and compare it to the chart on the item webpage.