These SK Hand Tool Black Oxide Combination Wrenches are designed for applications where a traditional combination wrench would be used, but due to the needs of the specific environment, require a black oxide finish. This finish will not flake, and can be used in environments where non-plated tools are required. Combnation wrenches with 12 point box end, these tools are available in both fractional/SAE and metric sizes. They meet or ecxeed ASME standards by 150 percent, according to the company.