Sterling Pacific machines their travel cases from 5052 aluminum, the same alloy used in aircraft fuselages for its strength-to-weight ratio and corrosion resistance. The body starts as 1.2mm aluminum sheets shaped under hydraulic pressure, then reinforced at load points with die-cast A380 aluminum corners riveted with over a hundred SAE 304 stainless steel fasteners rated to 26,000 psi shear strength. Italian full-grain leather from a Veneto tannery wraps the top and side handles, developing patina instead of wearing out. Dual thru-axle wheels recess into the aluminum body to absorb impact forces that destroy plastic luggage after a dozen trips. The retractable trolley slides into a die-cast aluminum housing rather than the injection-molded plastic competitors use. TSA-approved double combination locks secure the ring-spun twill interior. Lifetime warranty backed by a repair shop in Reno where every case carries an engraved batch identification number. Comes with leather care wax and aluminum pen.