The Galaxy Audio CM-C200 Check Mate Calibrator is used to correct base measurements lost over time on your meter. It meets IEC 60942 2003 Class 2, ANSI S1.40-1984 standards and is designed to handle 1/2" and 1" microphone capsules at 94 dB and 114 dB. This accurate and easy to use calibrator comes in a handy carrying case and ready to go with batteries included. It works with any CheckMate SPL Meters and many other brands.