Sterling 2 Ton Mechanical Screw Jack STERLING JACK has welded steel construction body.Reduces metal fatigue allowing for a longer use of life. Can be used in any position upright,horizontal & Angle position. Unique design offers increased stability and safety. Screw mechanism rotates on a ball thrust bearing so it reduces friction. Positive drive : No slippage,Jack is tested for 120% of its rated capacity,Is safe!