The Gold Line GLPN is a handy, small pink noise generator/tester built into an XLR microphone connector! It's pocket sized, rugged and provides continuous pink noise plus a phantom power indicator. The GLPN, when time averaged, produces levels of plus or minus 1dB making it an excellent standard for "Flat" response. With the GLPN the user can adjust equalization and speaker crossover points and balance systems. This handy product can be used for sound masking systems and to provide greater privacy. It has also been utilized to help employees with tinnitus. The GLPN is phantom powered and whenever Phantom Power is present the LED on the back will light, if the LED does not light then phantom power is not present.