26 4 DU CMC 2 & 26 4 DU CMC 4 -

Thanks for writing in. Remove the channel balances from the window and send us photos of the nylon attachments at both ends of the metal channels. The combination of attachments determines the kind of channel balance you need. Note all of our channel balances come with the fittings already attached out-of-the-box. Let me know if you have further questions.