Hello there. Based off the end attachments, I believe your channel balance is an S395-29 with a stamp option of 2840. Your question about the first two digits in the stamp is a good one. The '28' actually refers to the height of visible glass in the window sash. The channel balance is typically 1" longer than this. As far as the Top Sash Guide, see if the 18-174 matches what you have. If it doesn't, please send clearer photos of your old guide from the front and side, and provide dimensions.
Unfortunately, this top sash guide is no longer made in white. The 18-174 is only available in black.
![How to Replace a Top Sash Guide [1080p]](../../images/videoThumbnails/107.jpg)
