English standard Metric, no more guessing which component was made where. Outperforms the old adjustable straight C-clamp wrenches without chewing the parts like a regular crooked vise! What else do you need to know other than this is Irwin's highest quality construction - the ultimate level of reliability for "gearboxes" anywhere in the world; whether it's repairing a tricycle or maintaining the structural integrity of a military aircraft. Instead, let me please you with a short story. Bought this model ok. In 1999, shortly after it was first invented, he passed it on to an acquaintance who fixed roadside bikes and sold them as a downtown spin-off. About a year later, he made the fatal mistake of asking in front of a motley crew of his roommates what we'd been doing for him lately. Everything from there apparently someone had to do and not engage in some kind of heated debate, harassment and did they really? Walked across the room, took the wrench and asked if he was done with it. . . He was immediately panicked when his two roommates burst out laughing.