Meade 16-Inch LightBridge (f/4.5) Truss-Tube Dobsonian Diffraction Limited Optics Meade optics consistently out perform telescopes of similar and larger aperture. Consumers know that Meade Optics Inside means that what they see through our telescopes will be views that are detailed, crisp and full of contrast. Meade Optical Coatings Aluminum Coatings with magnesium fluoride over coat provides bright images full of detail. 2" Crayford-Style Machined Aluminum Focuser with 1.25" Adapter Smooth precise focusing is achieved with this classic design. A unique focus tension knob and focus lock design gives complete control over focus. Built-In Primary Mirror Cooling Fan Bring the telescope into thermal equilibrium quickly and efficiently with the battery powered cooling fan. The fan is mounted to the rear of the vented primary mirror cell for fast cool down. Steel RA Roller Bearings, Roller bearings make movements smooth and effortless.