EGR states that the EGR RollTrac is weather-proof. The EGR RollTrac should not leak through the top slat surface, the side rails, canister, or the drainage tube system. However, as we do not conduct each and every fitment ourselves (unit assembly and placement onto the vehicle), we cannot guarantee the integrity of the fitment, and therefore will not guarantee the product will be 'waterproof'. Perimeter sealing and overall gap filling is the responsibility of the fitter you have hired to complete the fitment. Keep in mind, your existing tub has holes with the front wall, floor, and a 10mm gapping around the sides and bottom of the tailgate also.