Need two new channel guides

Thanks for posting. This looks like an S380-25 or S385-25, depending on the depth of the bottom nylon shoe. See below. Measure your old balance's shoe depth to see what matches best.

Comparison of the S378, S380 and S385 balance shoes.

You then have to choose a stamp option, which reflects the strength of the balance. Your old balance's stamp of 24-9 is from an outmoded rating system. To know what rating to choose, weigh the window sash your balance's support. You can use that weight to choose the right stamp option.

Yep! Based on the 1" shoe depth and the sash weight of 25 pounds, the S380-25 channel balance with a stamp of 2450 (24 through 27 pounds) is what you need. Let us know if you have further questions.