Includes Small foam windscreen;  wrist strap;  3 x AA batteries;  calibration certificate; Features ANSI & IEC Type 2 accuracy;  30 to 130 dB total dynamic range;  Two 70 dB measurement ranges;  A & C frequency weighting;  Slow, Fast and Impulse time weightings;  measures instantaneous (Lp) and maximum (Lmax) noise level;  large digital display on 128 x 128 dot matrix screen;  bar graph showing instant and max level;  display of last 1 or 5 minute sound level trend;  AC output signal to other devices;  powered from 3 AA batteries;  digital output of current sound level via USB;  tripod mounting socket;  stores up to 100 runs in non-volatile internal memory;  stores 1 sec maximum A and C weighted levels;  over 419,000 results stored in memory with up to 65,000 samples in a single run;  upgradeable to CEL-244 or CEL-246 model by return to Casella CEL; The CEL-242 is an advanced version of the CEL-240 sound level meter and is ideal for use in many situations where a quick idea of the current noise level is needed. It features 2 ranges from 30 to 100 db and 60 to 130 db and provides the standardized A and C broadband frequency weightings required by many protocols. The CEL-242 also has the Slow, Fast and Impulse time responses. A maximum hold function with a user reset is available to capture the highest level of noise to give a "worst case" measurement if needed. Results are displayed on a graphic LCD in either alpha numeric format or as a scrolling time history graph with either 1 or 5 minutes time history so that recent peaks and troughs may be viewed. Calibration is as simple as placing the calibrator over the microphone and switching it on. As soon as the calibration tone is steady it is automatically detected by the CEL-242and the user is offered the choice of performing the calibration with a single button press. There is no need to use old fashioned screwdrivers that may get lost as the calibration takes just 5 seconds and is very easy to perform.The CEL-242 adds on board storage capability at fixed 1 second intervals of the maximum sound level with both the A and C frequency weightings and the user selected time response to provide a low cost data logging instrument. Up to 99 runs can be stored, each of up to 18 hours maximum continuous duration per run depending on the amount of memory used so far. All runs are stored in memory and tagged with the start date and time using the meter's real time clock so they can be correctly identified when the unit is connected to a computer.The CEL-242 is provided with a standard quarter inch socket so that it can be mounted on a tripod or other similar fixtures in a secure manner. A small foam windscreen provided as a standard accessory protects the microphone from wind induced errors when making measurements and a wrist strap minimizes the risk that the meter will not be dropped when in use. Analog ac and optional dc outputs are available to connect the CEL-242 to other pieces of equipment and a low power digital output is also provided through the USB interface which can also be used to power the meter if required.