What do you guys with very heavy campers use for jacks?

[Sparse Gray Hackle]

Tried and true Happijac screw drive here. 13 yrs old and work fine.

In some parts of the world, they are referred to as Crappi Jacs. I suspect that is because of the motors. I had one motor that locked up after periods of no use. The factory recommended fix was to use the manual crank to break it loose.