Abstract: A truck tunnel (12) for a pickup truck (14) having a cab (16) with a rear window (18) in a rear wall (20) and a camper cap (22) on a bed (24) of the pickup truck (14) with a front window (26) in a front wall (28), spaced by a predetermined gap (30) from the rear wall (20) of the cab (16). The truck tunnel (12) comprises an inflatable apertured structural component (32) that is insertable into the predetermined gap (30) between the rear wall (20) of the cab (16) and the front wall (28) of the camper cap (22) and can be manipulated to extend about the rear window (18) in the rear wall (20) of the cab (16) and the front window (26) in the front wall (28) of the camper cap (22) to form a weatherproof and windproof seal therebetween.