||The method of measuring vertical displacement in a bore hole developed by ROGERS and LA CHAPELLE (J. Glaciol., 13,315,1974) has been adapted for core holes in polar ice sheets. The method uses metal bands injected into the hole as markers. The markers are located using a sensor consisting of an inductance coil in a tuned circuit that is detuned by mutual inductance as the coil approaches a conducting metal band. The principal change compared to the earlier instrumentation was an up scaling in size to accommodate a larger hole diameter and more robust construction of the components. Based on our experiences we suggest an improved band injection method.