Electrically conductive acrylonitrile butadiene rubber (NBR) compounds filled with different concentrations of fast extrusion furnace black (FEF) were experimentally investigated. The percolation concentration of the investigated composites was found to be 65 phr. Of all composites examined, sample N70, which apparently belonged to the region of percolation phase transition, was found most sensitive to compressive strain. The electrical conductivity of this sample was changed by more than 50% upon a 16% compression. Sample N70 showed a good reproducibility after preconditioning rather than before preconditioning. The piezo-resistive effects practically are thermally stable within the interval of 297-308K. The working range of load pressure, for sample N70, from 5 to 25 kg and the working voltage from 30 to 150 V. (C) 2007 Elsevier B.V. All rights reserved.