The Tuff End balloons feature seamless heavy-duty construction to meet the strict demands of the commercial shipping industry. The ends of the Tuff End balloon are made from molded vinyl with injection molding, tested to a tensile strength of 2000 psi, the strongest in the industry. Tuff Ends have large rope holes that accommodate standard shackles. The curved design hole prevents balloon swelling. The recommended pressure is 2 psi.