Electromagnetic exciter with internal built-in plezoelectric accelerometer (shear type) for servo regulation of vibration amplitude; frequency 150.2 hz porm 1.0 percent; warm-up time less than 5 seconds; 9.0 volt alkaline battery; battery life approximately 60 calibrations of 2 minute duration with automatic switch-off at the end of each calibration; length 150.0 mm, 5.900 inches; diameter 52.0 mm, 2.050 inches; weight 500.0 grammes including battery and leather case; accessories furnished leather case 1, 9v battery 1, 10-32 unf steel stud 1, mounting disc adaptor 1