Bearings: (2) 3282lb static rated Cam Follower bearings on load bearing end with (2) ball sealed roller bearings for guides.Decking: Modular deck with center BEDTRAX & WEATHERDECK our exclusive composite light weight decking is durable in all elements. Includes (6) D-Ring Tie-downsExtension: 3/4Multiple locking positions for safety and convenienceProfile: 4.5"Sizes in Length: 58" - 75"Sizes in Width: 39" - 48"TRAXRAILS: Not includedWarranty: LIFETIME with registrationWeight capacity: 1000lbs (evenly distributed)