This tool is made of dependable, long-lasting chromium molybdenum steel, which stands up to high-torque tools. The wobble extension, which comes in a variety of sizes, has a steel ball retainer, giving you the confidence it won’t slip off your impact wrench. No more fiddling around with u-joint extensions or sockets. No more loose fits or unstable socket/u-joint/extension assemblies that ultimately don’t work and leave you frustrated, with a couple of busted knuckles to boot.