Rubber piece that works with pivot bar

Thanks for reaching out to us. Are you referring to that broad black piece you show next to the pivot bar here? If so, I'm sorry to say that we don't sell anything like this and I've never actually encountered this myself. Most pivot bars just screw directly to the sash; I can't think of many examples where they require a subsequent piece to work with them, and those few examples that come to mind don't resemble this piece.

Can you go into more detail as to exactly what function this serves? Can you show me a photo of what it looks like installed? Finally, would you happen to know who made the window? I can't guarantee that we can find this for you, but I will do my utmost best.