Fowler's " U" -frame Deep Throat Micrometers are available with depths of 6" and 12" . Use Deep Throat Micrometers for taking accurate measurements of steel and plastic sheets and plates whenever a depth measurement of 2" to 12" is needed.Hamm ertone blue baked enamel frameGraduations are microfine on satin chrome finish for easy readingAll models feature a ratchet stop thimble for exact and repetitive readingsThe spindle thread is hardened, ground and lapped. The anvil and spindle are hardened and precision ground with microlap finish on carbide tipped measuring facesPositive lever locking clamp ensures reliable measurement at all timesWrench furnished with each micrometer for fast, easy zero adjustment on the sleeveSupplied with ball anvilMeets or exceeds Federal accuracy specs.Includes case.