If you have a truck cap or tonneau cover and want to keep out dust and water from your truck bed but you occasionally use your truck for transporting loose material, then this is the solution. ROK BLOCK XL installs over the tailgate gap and patented Ultimate Tailgate Seal with Taper Seal installs on the sidewalls. Both seals adhere using automotive grade 3M ST1200 tape. For drop in bed liners ROK BLOCK installs under the liner. Some parts in this kit are not compatible with the following pickups: Chevrolet Colorado, GMC Canyon, Ford Maverick, RAM, RAM with RamBox, RAM with Multifunction Tailgate, Nissan Titan, Honda Ridgeline with Dual Action Tailgate, 2020 and newer Chevrolet Silverado 2500 and 3500, 2020 and newer GMC Sierra 2500 and 2500, Toyota Tacoma and Toyota Tundra. To buy ROK BLOCK XL only, search ASIN: B075PWVW67. NOTE: For Ford F150, F250, F350 and F450 it's recommended to use 4.25" width ROK BLOCK (search ASIN: B00BPE4AP6). Also available 10.8 cm / 4.25" width ROK BLOCK with Tailgate Seal (search ASIN: B00R8KBV9Y) which fits select pickups in the U.S. market. Apply when the air and surface temperature is between 55° - 104°F (13° - 40°C). This product requires 25 lbs. of pressure to bond adhesive. Patents pending. MADE IN USA.