Special locking pliers clamp securely to any convenient object. Range: 1". Graduations: .0011. Reading: 0-100This checks ball joint wear and disc rotor run-out. Also checks gear backlash, valve guide wear and camshaft wear. With optional attachments checks tire and wheel run-out. Eliminates vibration problems and false readings by mounting directly on spindle. This set comes packaged in plastic blow-molded case.