3.0" Extension for 6 Ton Bottle Jack3. 0 inch Jack Extensions are sized to slip over the ram of a bottle jack or hydraulic cylinder and extend the ram 3. 0 inches so the jack can sit firmly on the ground while the load is lifted. This extension can be stacked on top of another extension to extend the reach. Since the parts are all fit together, the jack is far safer and less likely to tip or otherwise fail. The extension has a jack point cup machined into the top to mate with most