Will this fit under my lowered car or truck?

At 45 inches minimum height, it'll tuck under most stock suspensions and light drops. If your ride is slammed, measure your lowest clearance point—door jamb or rockers—and compare it to 45 inches before ordering.

How stable is this when I'm working underneath?

Steel frame stays rigid during use. Don't rely on it alone for safety—always use jack stands rated for your vehicle weight as a backup, especially on suspension or exhaust work.

Can I adjust the height while I'm lying on it?

Adjustment mechanism is not detailed in the specs. Test the ease of height changes before getting under the car—you may need to roll out, adjust, then roll back in depending on the locking system.