Strong, durable, and sturdy, the BULLDOG 12,000 lbs. support capacity square jack is the BIG reason why BULLDOG has carried the load in agricultural, construction, heavy-duty utility, and horse/livestock trailer industries since 1923. All BULLDOG 4" square jacks are rated for 12,000 lbs. support capacity and 10,000 lbs. lift capacity. The strength of the product, plus the wide variety of styles, makes this jack the best choice in its product class.