The performance of original manufacturer's electrodes and refurbished electrodes used by extra-corporeal shock-wave lithotripters were compared based upon their ability to erode uniform test stones. By having the stones erode rather than shatter, measurement of stone weight loss as a function of shocks could be obtained and compared. There were no significant differences in the mean erosion rates produced by eight original Dornier electrodes and eight refurbished electrodes (Lithotech*, Atlanta, GA). Functionally, the refurbished electrodes appear to be equivalent to the original electrodes. Measurements of test stone erosion rates also appear to offer a valid, indirect alternative to the measurement of peak pressures.