An airbag device includes an airbag and an inflator disposed at a side of a base portion of the airbag for inflating the airbag. The driver has a plurality of bumper tabs, each of the bumper tabs having an arcuate first contact surface that is formed about a tab axis, each tab axis being generally perpendicular to a translation axis about which the driver translates. The first wick holder assembly includes a first projection and the second wick holder assembly includes a second projection opposite and corresponding to the first projection. The coupling mechanism including an aperture and a pin that can be moved into and out of the aperture. The summing circuit algebraically adds the output signals of the voltage and current probes, and produces an output signal representative of only one of the transmitted waveform or the reflected waveform.