This is a big (3-1/8") double-hexagonal socket. It weighs about 5 pounds. Certainly it's made to tackle a big nut. Thanks to Rickey at the HRT gas shop for letting me take some photos of his tools. Professional mechanics provide their own tools. They have large mobile tool boxes with thousands of dollars of their own money invested to get their work done - kind of like photographers. Canon 40D, 1/60 sec @ f/3.5, ISO 800, 50mm lens.