The beauty of this device is that it just requires a phone call to activate. Designed for audio surveillance, the ZRAD GSM SIM CARD Audio Surveillance Spy Ear device is a special system designed for audio surveillance or monitor by providing regular mobile phone SIM services. It has a magnetized core which helps itself easily fixed on any hidden metal surface.
Has an embedded sensitive microphone, which can pick up any ambient sound. When the need comes, just dial up the SIM number, it runs silently at any circumstance, and help you capture needed sound of its surrounding. Its internal battery could provide 2~3 hours working time. With external extra battery, it is capable of constantly running up to 6~7 hours.
More details can be found at the vendor's site at http://vavolo.com/
