Feature: 1. When audio signal input is detected, the relay is closed. After the audio signal disappears, the relay delay (adjustable from 0.1 to 9.99 seconds) is disconnected, which is easy to operate. 2. Wide range of applications, in addition to for Android phones and PC, it can also be applied to various audio output scenarios such as automobiles and industries. 3. Made of highquality materials, strong and durable, has a long service life. 4. With small size, easy to carry and store, convenient to use and with good performance. 5. With a protective case to reduce the damage caused by falling from a high place. Specification: Item Type: Relay ModuleMaterial: ABS+PCB Adjustment Instructions: Press K1 for the first time, the nixie tube flashes -1, indicating that the sensitivity is adjusted, from 1 to 9; press K2 to increase and K3 to decrease to adjust (the factory default is 5) Press K1 for the second time, the nixie tube flashes 12.5, the tens digit flashes to adjust the tens digit of the delay time, press K2, K3 to adjust Press K1 for the third time, the nixie tube flashes 12.5, the ones digit flashes to adjust the delay time and the ones digit, press K2, K3 to adjust Press K1 for the fourth time, the nixie tube flashes 12.5, one digit after the decimal point flashes to adjust the delay one digit after the decimal point, press K2, K3 to adjust; Press K1 for the fifth time, the adjustment is completed, and the digital tube displays the measured audio value in real time. Package List: 1 x Relay Module Note: For iOS 7 and above series need conversion head