Description: 5.5 ft fleetside. 8 ft fleetside. 6.5 ft stepside. 6.5 ft box. 8 ft box. Avalanche, Escalade EXT. With 4ws & without composite. Hummer H3. Silverado, sierra hybrid. Helps align and secure your vehicle's cargo box panels This GM Genuine Part is designed, engineered, and tested to rigorous standards and is backed by General Motors