Extech vb300 3 axis g force data logger extech vb300 the extech vb300 3 axis g force datalogger uses a 3 axis accelerometer to record the time when shock occurs and can compute real time spectral data using an fft supplied with a magnetized bolt on mounting base 3 6v lithium battery and analysis software windows reg 98 2000 xp and vista compatible extech vb300 vibration data logger