Shower door bottom?

I think we can help. I would start by looking at our 10-324, 10-325, or 10-326 depending on what length you need. Now, these are meant to screw onto the door frame, but I don't see screws on your existing sweep. Is it held on with a double-stick tape of some kind? You can install our shower door sweeps the same way, if you'd prefer. You can pick up double-stick tape at any local hardware store.