Today, there is a need to know just how loud your surroundings really are. The CHECK MATES are inexpensive tools everybody should own. The CHECK MATE series SPL (Sound Pressure Level) meters, first introduced in early 2003, allow musicians, sound contractors, and others to measure SPL in decibels (dB). A decibel is defined as the unit for measuring relative loudness of a sound. We have expanded our line from one CHECK MATE SPL Meter to four produ...