Windshield gasket

If you can't find one, you might be able to salvage your old one if it's not torn. It takes a lot of elbow grease and solvent, but the originals are tough and beneath all that sealant, polish, paint and dried surface I found a soft, pliable rubber that looked like new.

I used lacquer thinner and it seemed to cut everything that was on the surface, albeit slowly. I used a flat screwdriver the width of the glass slot to scrape out old sealant that was softened by the solvent. It took perhaps three or four hours, a pint of solvent and several old towels to get mine really clean but it was much cheaper than a new one and after three years still looks good.