Abstract: An assembly (10) is disclosed including first slides (38) secured by bolts (64) to a topper (26) and second slides (36) secured by bolts (68) to the side walls (18) of a pickup truck (12). The first and second slides (36, 38) are of a tubular shape, with each of the first slides (38) further including first and second vertical legs (44) located on opposite sides of the second slides (36) and a horizontal seal leg (46) for sandwiching a seal (66) against the topper (26). First connectors (50) having female head portions (52) and second connectors (60) having male head portions (62) horizontally slideably received in the female head portions (52) include tabs (54) slideably received in the ends of the tubular shape of the slides (36, 38) and secured therein by the securement bolts (64, 68). A tubular weatherstrip (88) is slid on a cross bar (90) held by L-shaped portions formed on the connectors (50) of the front ends of the second slides (36).