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. Boughtβ¦