MANUAL JACK
A manual jack is one that lifts and lowers the tongue using a hand crank. With a manual jack like the Blackout 2,000 lbs Side Wind Swivel Mount Jack you have to use your muscles to level your trailer perfectly. The amount of rotations you must turn is determined by the gradient you are on and the height or lowness of your hitch. While manual jacks are physically harder to use, some people like the workout they provide. They also tend to be cheaper and possibly more durable than electric jacks because there are fewer parts to break.
ELECTRIC TRAILER JACK
An electric jack is a gear-driven device that does all the work for you with the press of a button. To function, the jack must be attached to your battery, and it can only be powered by a 12-volt source. There are also some excellent drill-powered jacks such as the Trailer Valet JX 2K Side which can be used without connecting it to your battery.