KJ05 is a passive speaker and requires an amplifier or receiver to produce sound. It cannot be connected directly to a turntable, computer, or phone. The speaker uses a 3 inch tweeter allowing for more room at the high-end. For bass, a 5-inch driver is used for smooth, rich, low frequency sound. Each speaker also has a bass reflex port that adds emphasis to the woofer. All provides more accurate reproductions of sound for the price point, complete with smooth treble & vocal clarity with low distortion. The KJ05 is designed to fit perfectly on shelf and desktops. Its well balanced sound signature and vocal clarity are a great fit with a wide range of usage scenarios, from background music to home theater. Amplifier is required and not included. Speaker wire is required. Material: MDF (Medium Density Fiberboard) Wooden body; Bass: 5 inch; Treble: 3 inch; Impedence: 4 Ohm; Rated power: 20W; Peak power: 45W; Sensitivity: 91dB/W; Frequency response: 50Hz - 20KHz; Each size: 6.1 inch x 6.1 inch x 9.84 inch (Pair); Each weight: 1.35kg (Pair).