The credit card size bug detector DD1210 is a tool to help you locate any devices that transmits a wireless signal. This device will detect GSM, and RF signals at a frequency range between 50MHz - ~ 3GHz. The unit offers four modes when it has detected a signal; silent, beeping, sleep and vibration; as soon as a signal is detected the unit will alert you with the mode of your choosing. This unit runs off of one single CR2430 watch type battery. GSM means "Global System for Mobile communications", and it is the standard currently in use more or less worldwide. In the U.S., the major providers using this standard are T-Mobile and AT&T Wireless. This device cannot differentiate bugs that send wireless signals from normal everyday household items such as, Wi-Fi and Bluetooth. It is recommended that you power down all your devices that send signals to help avoid false positives. Be sure to check out our wide variety of bug detectors.