Thicker gearbox, manufactured from 1/4" thick material gives greater structural rigidity to improve jack life under heavy loads Hardened wear washer used under gear improves jack life under tension loads. Oil-ompregnated flanged bushing centers the screw stem to improve bearing and gear life by maintaining screw postion. Heavy-duty drop leg pin increases support capacity to 7,000 lbs. Direct weld to outer tube is standard.