2 x 2 inch square entry size, which is the size for most 4WD cars and pickups. Cars it fits: This hook can be installed on most 4WD (SUV) and pickup trucks that have a 2-inch receiver. These include: Toyota: Land Cruiser, Prado, Fortuner, Shas/Raba (if a rear square hook is installed), and Sequoia. Nissan: Patrol, Armada, and Navara. American (GM / Ford / RAM): Tahoe, Yukon, Sierra, Silverado, Ford F150, and Wrangler/Grand Cherokee.