This meter has everything you need to start measuring sound. It also includes a sheet explaining the different settings and what they mean, such as: B. Different tone reports - average or maximum, called A or C. I found it to work as the instructions said it would. The BTMeter is said to come calibrated, which is good. during a year. I am unable to produce calibrated audio so I took the company's word for it. I ran what is called a sniff test to measure sounds where I have a reasonable idea of their level. For example, my 22 year old truck with mud and snow tires should average 70 or 80 seconds (slow) at a cruising speed of 65 mph. And so it was. If it measured 68dB like a Lexus or 110dB like a Who concert, it would have failed my mind or smell test. While this meter has a good range for almost all applications, it fell short on one occasion. My sister wanted to measure several noise levels of her silenced (silenced) and non-silenced firearms, which she had just received after months of waiting for BATF approval. It turned out that even with the supposed "silencer" of firearms, 130 dB of the maximum power of this device was exceeded. While the meter couldn't measure it, others within range said the sound level could easily exceed 170dB(!) without restriction, and maybe 135dB with a silencer. It seems to me that measuring noise, not just from firearms, loud enough to damage hearing would be a good use for a sound meter, so I'm a little disappointed that this instrument isn't being used for that purpose can. Tip: When you get yours, you unexpectedly measure the sound level in the kitchen. Household appliances, in particular blenders.