While many general-purpose 100 mV/g accelerometers carry a low frequency -3dB specification of 0.2 Hz to 0.5 Hz, they are not the best choice for accurate measurements on slow-speed machines. That is because most general-purpose 100 mV/g accelerometers also have a much higher low frequency noise level than accelerometers designed for low frequency measurements. The 500 mV/g low frequency accelerometers should be used as they have much better signal-to-noise ratios.