I got the 6 ton bottle jack but if you already have a bottle jack you can just get the extensions. The extensions are solid. As mentioned, I've spent more on things that do work but did not accomplish my ultimate goal of having something compact and usable under more circumstances.
At Easter Jeep Safari a group from a local Salt Lake City Jeep dealership dislodged the engine from its motor mount. I showed up with this Jack at the same time one of their co-workers ran off to pickup some lumber and a floor jack. The reach of the extensions they were able to get the motor back on its mount and the repair done before their co-worker returned. we we're all impressed how well it worked.
6ton jack seems to be enough I have a 12 ton jack at home, i ordered the 12ton adapter just in case i decide to use it.