Help with shower door!!!

[muzbomb]

Hey guys i have an issue with my shower/tube door in my bathroom. There is a little plastic/rubber clear piece that goes under the door mine is ripped off. It looks like it just slides in a channel. It is the piece that goes between the door and tube when closed. My dealer says they cant find a part# for just that piece. Anybody know or have a fix for this?? Is there something else i can use that i can just buy from a hardware store?? THansk guys!!