They sure make that confusing. This was on the 7" description. Mine is installed and I am happy with it so far, but if you order one, you might want to call and ask what is best for your truck.
The original tailgate gap cover, since 1999, "ROK BLOCK XL" bridges the gap between the truck bed and tailgate preventing the loss of materials such as gravel, dirt, mulch and sand. 7" width is compatible for most pickups worldwide including Chevrolet Silverado, GMC Sierra, 2021 and newer Ford trucks with hinge retainer bracket, Ford Lightning, 2019 and newer Ford Ranger, RAM 2500 and 3500.
Not compatible with 9 pickups (Use 4.25" width ROK BLOCK): Chevrolet Colorado, GMC Canyon, RAM, RAM with RamBox, Ford Maverick, Jeep Gladiator, Nissan Titan, Toyota Tacoma and Toyota Tundra. Excluded pickups for both ROK BLOCK and ROK BLOCK XL (2): Honda Ridgeline with Dual Action Tailgate and RAM with Multifunction Tailgate.