Double hung vinyl window stripping

I hope you can help me. This came off the bottom of my 23 yr old Simonton vinyl window. It slides on the very bottom of the window and when the window is down it keeps the rain, etc out. In picture#1, it is the outside part. It is suppose to have rubber on the piece on pic#2. I'm needing to replace this strip on several of my windows but can't find it at Lowe's or Home Depot.