Powerbuilt Zeon sockets are designed to grip and turn damaged and rounded nuts and bolts. The patented design will grip and turn hex heads up to 85% rounded. And they work just as well on new nuts and bolts. In other words, if you’ve got a bolt that you can’t turn or a nut with rounded corners, we have the help you need. The secret is the patented Zeon socket design - the more you turn them the harder they grab and hold damaged hex heads. Zeon sockets are heat-treated to hardness HRC 38-56 for maximum strength and durability.