The field calibration of Sound Level Meters is an essential procedure when carrying out any type of noise survey both before and after each measurement sequence. This ensures that instruments are providing consistently accurate readings necessary for monitoring to ensure compliance with workplace and environmental noise regulations. The CEL-120 is therefore designed and manufactured to comply with the requirements of IEC 60942 2003 and ANSI S1.40 2006. These standards stipulate accurate calibration over a wide range of temperature, humidity and pressure conditions, typical of field work, ensuring accurate calibration in all conditions. The CEL-120 is compact and ergonomically designed with simplicity and ease of use being the highest priorities.