Rated output: 20 W; Power supply voltage: DC 24 V; Input circuit: MIC 600 Ω x 1 (standard jack); Load impedance: 4 - 16 Ω; Dimensions: W 7.0 x H 2.0 x D 6.5 inches (178 x 50 x 164 mm); Weight: Approx. 2.4 lbs (1.1 kg); Accessories: Equipped with dynamic microphone, you can repeatedly broadcast MP3 lbs (1 kg). SD card is thinner and smaller than cassette tape, making it easier to select songs. It is strong for continuous playback and does not roll up tape. Use your computer to write music and messages to an SD card. Message holds up to 10 messages. It comes standard with a mute function that automatically attenuates audio volume when microphone broadcasting or handbrake is off. (NOTE) Digital audio specifications are MP3 format. SD card not included. Some SD cards cannot be played with this device.