CURT square jacks are a heavy-duty trailer jack option. They are designed to weld directly onto the frame of your trailer for superior holding strength. These heavyweight models have support capacities ranging from 8,000 lbs. up to 12,000 lbs. and lift capacities between 7,000 lbs. and 10,000 lbs., depending on the model. CURT square jacks are available in side-wind or top-wind handle options and are an excellent choice to meet the high demands of the farming life and construction industry.