LC3 UC06 is an affordable, general-purpose 6w ceiling speaker suitable for a 100v connection line with 6, 3 and 1.5 watt power taps. LC3 UC06‑LZ is a low impedance (4 ohm) ceiling speaker that can be directly connected to the output of a low impedance amplifier. The optional bottom box, LC3‑CBB, fully protects the speaker from dust and falling objects and prevents sound from propagating through the ceiling pores to adjacent areas. The speaker frame, mask and bottom box are made of flame retardant ABS material and meet UL 94V0 standard. All Bosch loudspeakers are certified to meet IEC 268-5 power amplifier (PHC) standards and can operate continuously for 100 hours at rated power. Bosch has also conducted simulated acoustic feedback exposure tests to ensure they can withstand twice the rated power in a short period of time. This ensures higher reliability in extreme conditions, improves customer satisfaction, extends service life, and significantly reduces the chance of failure or performance degradation. CE conformance declaration safe in accordance with EN 60065 regional certification European CE installation/equipped with a built-in spring arm for ceiling speakers that can be firmly fixed to the ceiling opening. The ceiling can be between 5 and 25 mm thick. In addition, a template is provided for accurate opening of holes in the ceiling. An electrical connection is made through a soft wire, each color of which is connected to a different connector that matches the transformer. The matching transformer provides three connections that can be used for 100 V electrical connections, allowing the user to select rated full power, half power and one quarter power. The optional LC3‑CBB can protect the back of the speaker from dust and falling objects, protect the speaker from insects, and prevent sound from spreading through the pores of the ceiling plate to adjacent areas. The bottom box is assembled with a speaker through an embedded structure with two opening holes for mounting washer (11mm) and two cable seal plugs (20.5mm).