Here's a heavy duty engine crane that has worked well for me for many years. It has a 3-ton ram with no leaks. It has an extendable top boom and four extendable legs, on steel casters. It was overloaded sometime in the past and the bottom frame is bent. It still lifts fine, but does not sit square, and does not roll like new. We have used it for 6 years like this, or it can be straightened.