SureGrip hex design drives the side of the fastener, not the corner. Black coating provides rust prevention. Improved access to hard to reach areas. Made in the U.S.A.. Lifetime warranty The SureGrip hex design drives the side of the fastener not the corner. This not only provides increased strength, but also avoids rounding of rusted or damaged fasteners, which can occur when using a sharp cornered hex tool. The black coating retains more rust preventative compound than black oxide.