Meade Instruments LightBridge 16-Inch Truss Tube Dobsonian Telescope, Open Truss - Black (1645-05-03) Open truss tube design with new anti-reflection coatings on trusses and castings 16-inch aperture and a focal length of 1829-millimeters Focal ratio is f/4.5 Laminated base features roller bearings on the azimuth axis Comes with a 1-year limited warranty