In-ceiling speaker system. You can choose the speaker panel (sold separately) that is best for your installation environment. Spring-catch system allows for easy installation by simply hanging the panels The plug-in connector allows you to wire wires with one touch, allowing for feed and branch wires. The ATT circuit adopts a trans-type, the amount of attenuation is consistent regardless of the input and there is almost no attenuation during emergency broadcasts. 5 levels of volume adjustment. It can also be used for system ceilings.