Double nutted, nearly doubling the speed of use. Lifetime warranty. Provides stability to travel trailers, fifth wheels, horse and cargo trailers. Large 5" x 9" footpads combat sinking and tiltingPowder coated black finish resists rusting3" x 10" multi-hole mounting platesStrong worm gear jacking mechanism won't slipBolts or welds to RV frameLifetime manufacturer's warrantyTwin pack includes hand crankNever use for lifting, only for stabilizing.