The JET Super Heavy Duty Professional Adjustable Wrench comes with an ergonomic handle that increases comfort and gripping power, while reducing your fatigue. The precision ground jaws grip fasteners better, which reduces rounding. This wrench's thin jaw build provides better access to confined spaces. There are S.A.E. and METRIC scales for quick and accurate adjustments. All components made of finest quality Chrome Vanadium steel. This Wrench meets Federal specification CDA 39-GP-13A, U.S. GGG-W-631B, and ANSI specifications.