The 9100C from The Modal Shop Inc., Cincinnati, OH, is a portable vibration calibration system for vibration sensors and proximity probes that produces NIST-traceable reports that comply with ISO 17025/A2LA requirements. The unit feature a rechargeable power source, the ability to set test parameters for calibrating sensors in a bandwidth from 10 Hz to 10 kHz over an amplitude range up to 10 g, an LCD readout of shaker amplitude and frequency, and the ability to support sensors that weigh up to 750 g without needing an external support mechanism. An optional S4A-1 attachment enables testing of noncontact displacement sensors.