Here is the specs on the Fulton Jack with the double wheel.
Quote:
F2 Twin Track Jack
Includes Handle Hold-Up & Wheel Wedge Features, & Bolt-On Mounting Hardware for 3″ x 3″ & 3″ x 4″ Frames
Fulton’s F2 is designed for use with marine, recreational and utility trailers, continues that Fulton heritage of innovation rethinking every feature and challenging industry conventions. The result is a reengineered high quality product that will transform the industry. It’s so strong and reliable that Fulton is backing it with an unprecedented Limited Lifetime Warranty.
Maintenance free – designed to eliminate the need for lubrication and maintenance.
Corrosion resistant coatings cover internal and external components – will hold up in salt water and other harsh environments.
Ergonomic design – crank, release pin and integrated wheel wedge are made of strong, engineered plastic for a comfortable touch.
Stylish design – compliment your boat and customize your trailer’s styling.
Sealed and lubricated one-piece gearbox.