JET 20-Ton Capacity SJ Series SCREW JACK -- Contractor quality mechanical jack for all-purpose lifts and supports. Holds heavy loads indefinitely - will not creep. Heavy-duty bell shaped cast base. Less effort required to lift capacity load with new design. Corrugated steel swivel head turns easily under load. Easy to carry and position with built-in handle. Compliance: ANSI/AMSE B30.1 standards