The Casella CEL-120/1 Acoustic Sound Level Meter Calibrator is a high-quality and reliable tool used for maintaining the accuracy of sound level meters. With its Class 1 calibration standards, this blue calibrator ensures precise measurements and complies with international standards. The unit quantity is 1, making it a single, standalone device that is essential for regular calibration and testing of sound level meters in various industrial and professional settings. The Casella brand is known for its commitment to quality and excellence in measurement tools, making this calibrator a trusted choice for professionals in the field.