Detailed instructions In order to satisfy customers' special requirements of siren volume and position, the host particularly increased external alarm interface. After external alarm accessing into the host, the strong sound of playing out when alarming owns the function of intimidation and prevention. Also can notice the neighbour, the theft are impossible to defend. Specifications parameters standard voltages:12VDC Standard current: 100-150mA sound pressure index:≥115dB(test range 300mm, environmental noise ≤65Db,standard voltage) Tone frequency: 3.8 KH2 + 10% Conversion speed: 3H2 ± 10%