1979 - 1987 GMC K3500 Windshield Weatherstrip Seal With Trim Groove For Lockstrip For Lockstrip. This windshield seal goes first on the body then the glass is placed in the opening. A separate lockstrip (not included) inserts into the rubber and secures the glass in place. Made from ozone resistant EPDM rubber and from the same OE specs as the original for an authentic fit and finish.