... . Horn specification: 4 Ω, 3w4. L196 × W83 × H52mm5. USB-powered supply: 2.5W * 26. battery-powered supply: 1.5W * 2 7. the system frequency ... response: 150 hz ~ 18 KHZ 8. power voltage: DC5V 500 ma/USB ... Accessories Available: housing,hansfree,charger,battery,silicon protector,screen protector,usb data cable, memory card, card reader,holder and etc. ...